Apple is launching iOS 4.2 today.

The company announced that its latest operating system update for iPhone, iPod Touch, and iPad users will be available today, though the software was not yet available for download at 7:00 a.m. PT on Apple's site or directly through iTunes. MacStories and MacWorld are reporting that iOS 4.2 will debut by 10:00 a.m. PT.

The eagerly awaited update will bring to the iPad new features that already hit the iPhone and iPod Touch through last summer's iOS 4.0 release.

iPad users will now be able to multitask by switching from one app to another, organize apps via folders, and more easily jump from one e-mail inbox to another. Owners of Apple's popular tablet will also be able to join Game Center, Apple's social-gaming service that lets people play games online with their friends.

"iOS 4.2 makes the iPad a completely new product, just in time for the holiday season," Apple CEO Steve Jobs said in a statement. "Once again, the iPad with iOS 4.2 will define the target that other tablets will aspire to, but very few, if any, will ever be able to hit."

iOS 4.2 is also bringing new features to all three of Apple's mobile devices.

People who've been asking for the ability to print now have their wish. The new AirPrint feature will print content directly from the mobile device to any AirPrint-enabled printer on a local network. That list initially includes the ePrint enabled printers from Hewlett-Packard, such as the HP Photosmart, HP LaserJet Pro, and HP Officejet, though Apple has said that iOS 4.2 mobile devices will be able to send data to any printer as long as it's connected through a Mac or PC. People can print documents, Web pages, photos, and other files. Apple is also touting the fact that no drivers, software, or cables are required to print via AirPrint.

The new AirPlay will wirelessly stream music, videos, and photos from an iPhone, iPod Touch, and iPad to the Apple TV box. Music can also be streamed directly to AirPlay-enabled speakers or to any stereo using AirPort Express.

Those worried about losing their devices can use the Find My iPhone feature, which also works for the iPad and iPod Touch. Freely available as a download through the App Store, this tool lets people find a missing device by locating it on a map and having it flash a message or play a sound. People can also remotely lock or erase data from their lost device. This type of feature was previously available only to subscribers of Apple's $99-per-year MobileMe service.

The actual launch date of iOS 4.2 was the subject of much speculation over the past couple of weeks. MacStories and other sources had claimed the update was set to debut on November 12. But the release might have been waylaid by a reported Wi-Fi bug that was rumored to have affected the iPad's ability to maintain a wireless connection. Apple pushed out a new Gold Master version for developers on November 12 and then another one this past Thursday.

iOS 4.2 will be available for the iPhone 3G, 3GS, and 4' the iPod Touch 2G, 3G, and 4G' and the iPad. Updating any of these devices with iOS 4.2 first requires iTunes 10.1, which Apple released November 12.

Updated 8:40 a.m. PT with further details and background.