Four people sit outside the Apple store on Fifth Avenue in New York at 12 p.m. ET yesterday, lining up for the new iPad 2, which goes on sale at 5 p.m. today.

The Apple iPad 2 hits store shelves at 5 p.m. local time today all over the country, and the second-generation tablet is already generating a lot of buzz with a few eager customers lining up outside some Apple stores at least a day in advance.

Unlike notable Apple product launches of the past, this time, the company didn't offer an extended preorder period. And it wasn't allowing customers to reserve devices weeks in advance of the sale. Instead, the company only began taking orders for the iPad 2 starting at 1 a.m. PT with orders expected to arrive at customers' homes sometime next week.

What does this mean for potential customers on launch day It could mean long lines at some stores with potential shortages of certain models and configurations of the iPad 2.

But Apple employees and workers at its retail partners say they're ready. Unlike last year's launch, when the original iPad was available in Apple stores and select Best Buy stores, this year, the iPad 2 will be also be available at Target, Wal-Mart, Sam's Club, Verizon and AT&T retail locations, and online at Amazon.com.

When we spoke with a sales representative at Apple's flagship store on Fifth Avenue in New York yesterday, where four people were already in line at noon, he was confident the company would have enough iPads on Friday evening to satisfy customer demand.

"I can't guarantee that we will have every model in stock," he said. "But we will be getting more over the weekend."

A sales associate at the Apple store on the Upper West Side of Manhattan said the store may sell out the first evening the iPad is on sale, but he said the store would get more shipments over the weekend to fulfill demand.

Across the street and down the block, a salesman at the Best Buy store on 62nd and Broadway in New York, said the store has more iPad 2s in stock for the launch than it had for last year's launch of the initial iPad.

While he wouldn't guarantee that the store won't sell out the first day or even the second day, he was confident that this particular Best Buy location had enough iPad 2s to meet a higher demand than last year.

"But there's going to be a line," he said. "If you want one, I'd show up no later than 2 p.m. just to make sure you get the one you want."

CNET reporters on both coasts will once again be tracking the lines that form and providing insight into the initial sales of the iPad 2. CNET reporter Marguerite Reardon and photographer Sarah Tew will be in Manhattan, while CNET reporter Josh Lowensohn and photographer James Martin will be providing updates from San Francisco.

Check out our coverage throughout the day and evening right here, where we will post updates as well as photos.

College student Chris Tantillo of Rockland, N.Y., was first in line at the Upper West Side Apple store in Manhattan. He was getting paid $25 an hour to hold a place in line for an eager iPad 2 customer. He had been there since 7 a.m. ET yesterday.

New York 1:30 p.m. ET: About three and a half hours before the iPad 2 goes on sale, there are between 500 and 600 people crammed into police barricade pens outside the Apple store on Fifth Avenue in Manhattan. Brian Ceballo and his cousin Joseph Cruz, both of Brooklyn, have been here since 8 p.m. ET on Wednesday night. They waited in the drizzling rain all day Thursday and braved a torrential downpour late Thursday night and into the wee hours of Friday morning to be the second and third people in line for the new iPad 2. The cousins did take shelter for a couple of hours inside the Apple store between 1:30 a.m. and 3:30 a.m. this morning.

Amanda Foote, a college student originally from Florida, was the only person ahead of them. She got to the store at 5:30 a.m. ET on Wednesday. I spoke with her yesterday when I checked out the line at the Apple store. But Foote was gone by 9 a.m. after she sold her first spot for $900 to Hazem Sayed, founder of the app developer Zami. Sayed has developed an iPhone app that allows people to chat with each other while standing in line. The $900 he spent to buy Foote's spot, which she originally advertised on Craigslist for $600, was part of a publicity campaign to get people to notice his app.

The line at the Apple store on Fifth Avenue in New York was at least 500 people deep by 2 p.m. ET on Friday as people gathered to buy the iPad 2, which goes on sale at 5 p.m. ET.

New York 2 p.m. ET: The line has started to grow beyond the caged-in barrier area right next to the glass cube at the Apple store on Fifth Avenue. Apple security has been setting up more barricades to fence people in along the the 58th Street side. Apple product launches have become old hat for security workers and businesses surrounding the Apple store here. And they seem to deal with the crowds without much effort or fanfare.

The line at the Apple store on Fifth Avenue in New York is growing. It started to wrap around the block along the West 58th Street side of the building around 2 p.m. ET, three hours before the iPad 2 goes on sale.

New York 3 p.m. ET: While I've been hanging out on the steps outside the big glass cube above the Apple store on Fifth Avenue, my colleague, CNET photographer Sarah Tew, checked out Apple's Upper West Side store a few blocks away at 68th and Broadway. Like the store on Fifth Avenue, hundreds of people are lined up outside the store waiting for the iPad 2 to go on sale at 5 p.m. ET.

The following are several pictures she shot from the Apple store on the Upper West Side.

At least 200 people waited outside the Apple store on the Upper West Side of Manhattan this afternoon waiting for the iPad 2 to be released.

Only a handful of people waited all night at the Apple store on the Upper West Side.

Food vendors lined up 67th Street in New York were doing good business as people lined up for the iPad 2.

New York 3:15 p.m. ET: After hitting the Apple store on the Upper West Side, Sarah strolled down to a nearby Best Buy store on 62nd and Broadway. Unlike the Apple stores, which were surrounded by people waiting in line, there was no one standing in line for the iPad 2 at Best Buy. Salespeople in the store said if she wanted an iPad 2, she could come back at 4:30 p.m. ET when they expected the line to form. The iPad 2 goes on sale at 5 p.m. ET.

A salesman on Thursday said the Best Buy store on 62nd Street should be well-stocked. Maybe some of the folks standing in line at the Upper West Side location should go to Best Buy instead.

There was no line at the Best Buy store on 62nd Street and Broadway in New York City just a few blocks from the Upper West Side Apple Store, where at least 200 people were lined up.

New York 3:30 p.m. ET: The crowd has continued to grow all afternoon at the Apple store on Fifth Avenue. The single-file line was starting to wrap around the block.

Two hours before the iPad 2 will go on sale, the line at Apple&39's store on Fifth Avenue was starting to wrap around the block as people lined up along 58th Street next to the FAO Scwhartz toy store.

More from the Apple store on Fifth Avenue as people wait for the launch of the iPad 2.

New York 4:30 p.m. ET: Apple has closed the Fifth Avenue store to regular shopping. And the employees downstairs below the cube are starting to cheer and chant in anticipation. Apple employees manning the line outside told me they have no idea if they have enough iPad 2s in stock to meet the demand at the store right now. The line of people is wrapped around the block down 58th Street along Madison Avenue to 59th Street. The apple employee we spoke to said they will be handing tickets out soon. And those who get a ticket will be guaranteed an iPad 2.

Apple has closed the store to regular shopping until after 5 p.m. ET.

New York 5 p.m. ET: Just before 5 p.m., Apple lined up its employees outside to cheer and clap as they counted down to the official launch of the iPad 2. And moments later the first iPad 2 customers were escorted into the store.

Apple employees started clapping and cheering about five minutes before they let the first iPad 2 customers into the store on Fifth Avenue.

Brian Ceballo and his cousin Joseph Cruz were the first two people in the Apple store on Fifth Avenue who were buying the new iPad 2. Ceballo and Cruz had waited in line since Wednesday evening at 8 p.m. ET.

New York 5:10 p.m. ET: The first iPad 2 customer at the Fifth Avenue store has emerged from the Apple cube with two iPad 2s in hand. Alex Scumilov came to the Apple store on Thursday afternoon to buy a MacBook Pro. But he ended up staying the night and waiting in line with about 15 other people for the new iPad 2. He was fifth in line, but was the first person to come out of the store. He said he was keeping one iPad 2 for himself and selling the other to a friend.

Alex Scumilov was the first iPad 2 customer to emerge from the Apple store on Fifth Avenue in New York.

San Francisco 3:45 p.m. PT (and switching from Maggie Reardon to Josh Lowensohn): This is CNET's third time checking in on the San Francisco store, but the first update. We swung by here last night around 6:30 p.m. PT, and there was no line to be seen. At around 8:30 a.m. PT this morning, there were 100 or so folks lined up in front of the store, the first of which had gotten there just after 4 a.m. PT. Now the line stretches well around the block, only to be broken up in a few places by parking garages, mailboxes, and sidewalk crossings.

The front of the line at the Apple store in downtown San Francisco.

At the front of the line is not the typical Apple fan. Instead, it was an enterprising young man named Josh Elavitti, who was doing a running job for paid errand service TaskRabbit. Elavitti was buying two iPad 2s for clients, one who lived just across town in Hayes Valley, and another who planned to snatch the iPad 2 just after sales began and take it on a direct flight to Singapore.

How much is this that 13-hour wait worth, you might be wondering Just $60 a piece from the two buyers, the majority of which will end up in Elavitti's hands. The rest, around $12 or so, goes to TaskRabbit.

In the middle is Jonathan Ive, Apple&39's SVP of industrial design.

Leonard Yeung is flying to Singapore tonight with his new iPad 2. He got it by spending $60 to have someone from TaskRabbit (Josh Elavitti) sit in line for him for 14 hours.

San Francisco 4:29 p.m. PT: Those who were sitting down near the front of the line are now up and ready to go. That includes a group of about 25 who were just graced with an Apple store employee who is going to act as a translator since they speak Cantonese, and not English. One of their bilingual group members, who was going to have to act as the translator for all of them, told CNET the move made his life much easier.

There was also a 20-minute or so demo session of iPad 2 apps by their developers, which Apple shut down after the iPad 2 demo units were swarmed by tourists and other passers-by looking to get their hands on the unit. Among the three were Chair, the makers of the hit game Infinity Blade, Firemint, who was showing off Real Racing 2 HD, and Synthetic Corp., which was demoing the new version of its Incredibooth photo taking software.

San Francisco 5:11 p.m. PT: Jonathan Ive, Apple's senior VP of industrial design, is here watching from the top deck inside the store. The first sale took eight minutes.

San Francisco 5:18 p.m. PT: Grabbing one of the first iPads was Elavitti, with whom CNET had spoken earlier. Right after he came out, he handed it over to Leonard Yeung, who was later catching a flight to Singapore. Yeung told CNET he intended to keep the iPad, and wasn't going to sell it, unlike a handful of other line-waiters CNET talked to who said they had already secured buyers on both Craigslist and eBay.

And here we have Josh Elavitti, with iPad in hand.

San Francisco 6:17 p.m. PT: The line here now wraps nearly around the entire block. CNET talked to the manager at The Body Shop, the cosmetics retail chain, who said he was pleased with foot traffic brought in from the release. The store had anticipated it ahead of time, though was also given a heads up by Apple last week. This happens every time there is a product release, he said.

iPad 2 buyers work their way inside the downtown San Francisco Apple store.

More than an hour after the device went on sale in San Francisco, the line was wrapping nearly around the entire block.

Others weren't so pleased though. An employee at Crate & Barrel, which is a few stores up the street from Apple's downtown store, told CNET that the store tends to get less foot traffic on launch days, with this launch being no different.

San Francisco 6:27 p.m. PT: I'm following up on rumor that there are no more white Wi-Fi iPads.

San Francisco 6:33 p.m. PT: The people at the front of the line have been here since around 2 p.m. PT. Sold out are 16GB and 32GB models of the white, Wi-Fi-only models.

San Francisco 6:36 p.m. PT: I also swung by the Verizon retail store earlier, which sold out if its stock in about 10 minutes. Employees there didn't know when they were going to have more, and they were not doing rain checks or reservations.

The following are more shots taken by our photographer James Martin around the time Apple started selling the iPad 2 here at the downtown San Francisco store (Enjoy while I take a break):

After the long wait, Apple starts to lower the black curtain inside the downtown San Francisco store. It&39's 5 p.m. PT sharp.

This shot shows the reflection of the crowd as Apple gets ready to let iPad 2 buyers inside.

A view from above after the first few iPad 2 buyers are let into the downtown San Francisco Apple store.

James Alimeda, who was second in line for a iPad 2 in at the downtown San Francisco store, was also one of the first to walk out of the San Francisco store.

Another shot inside the downtown San Francisco Apple store just after iPad 2 buyers were let in.

San Francisco 7:55 p.m. PT: The line now stretches completely up the block and around the side a bit, but not completely around the block as it did before. Part of the reason for that is probably because all the Wi-Fi-only models in both colors are completely sold out. All that remains are all capacities and all colors of the 3G models on Verizon's network and the black 64GB model on AT&T. One salesperson told us "we have tons of Verizon, in both colors." They have all colors of Smart Covers in stock.

That's a wrap for now from San Francisco. Stay tuned for a post-game story about the overall iPad 2 sales launch. Thanks for reading, and please feel free to send us your stories (and photos) or leave them in the comments below.