A Wi-Fi bug has reportedly sidelined Apple's iOS 4.2 update, which was rumored to be launching today.

MacStories, Engadget, and other blogs have pinned the cause of the delay on a Wi-Fi connectivity bug affecting the iPad. Users who've been testing the Gold Master release of the update on Apple's popular tablet reportedly have been able to establish a connection but not able to actually connect to anything, or are simply losing the connection after a few minutes.

Though Apple never announced an official release date for iOS 4.2, CEO Steve Jobs has said that it would be coming in November. On Tuesday, MacStories claimed that an AT&T insider had told it today would be the launch date.

But iTunes 10.1 is required for certain features in iOS 4.2, including AirPrint, which would let iPhone, iPod Touch, and iPad users print to their local printers via their home Wi-Fi networks. Several reports had pegged Wednesday as the date that iTunes 10.1 would be available. But as of this morning, iTunes 10.0.1 is still listed as the current version on Apple's iTunes download site. Checking for updates within iTunes also indicates 10.0.1 as the current version.

iPad users have been awaiting iOS 4.2 as the release that would finally bring them folders, multitasking, and a host of other features that iPhone and iPod Touch users have had access to since iOS 4.0 was released this past summer.

But iOS 4.2 will also offer iPhone, iPod Touch, and iPad users AirPrint and AirPlay, a feature that will wirelessly stream audio, video, and photos to other devices on a Wi-Fi network. Even iPhone 3G owners are supposed to benefit from the new update though an improvement in performance.

With the Wi-Fi connectivity glitch purportedly now delaying the release, MacStories says that Apple could roll out a second Gold Master build to deal with the issue as early as tomorrow. But even with extensive testing, the site expects the final release of iOS 4.2 to be out before Thanksgiving.