Current ship times for Wi-Fi versions of the iPad 2 are two to three weeks, and could continue to be pushed back.

If you were expecting to be able to pick up an iPad 2 from Apple between now and April, your best bet may be to get in line at a local retailer.

Just hours into the iPad 2 going up for sale on Apple's online store, the company pushed back ship times across the entire line of devices from two to three days, then five to seven business days, and now two to three weeks. That lead time could stretch even more with shoppers putting in orders throughout the rest of today and into the weekend.

Similar availability problems faced the first iPad, with Apple being unable to keep up with demand. Back then, shipping times did not come down to the magical 24-hour mark until the end of August, some four months after the device had gone on sale in the U.S. In the process, Apple sold more than 300,000 iPads on its first day of availability, and hit 1 million units sold in 28 days. That unexpected demand had also prompted Apple to push back its international release of the device, so as to keep up with sales.

Along with Apple's online store, Web sales of the iPad 2 at Apple partner retailers like Wal-Mart are likely to face similar supply restraints when the device goes on sale later today at 5 p.m. ET. We'll be keeping track of that, along with the scene at a number of retail outlets across the country throughout the day over at our semi-live blog.