Macstories is reporting that an AT&T source told them iOS 4.2 for iPhone, iPod Touch, and iPad will be coming to iTunes at 10am pacific / 1pm eastern this Friday. iOS 4.2 was recently released as a gold master version to developers, so we all knew a public release was imminent. It seems likely that the OS update will arrive on Friday or at least sometime soon. iOS 4.2 will bring AirPrint, AirPlay, and other improvements to the iPhone and iPad. Plus, it will finally bring all the features of iOS 4 -- multitasking, folders, unified email, Game Center -- to iPad.