Apple has released iOS 4.2 GM for all devices today (as well as Xcode 3.2.5 & iOS SDK 4.2 GM). Apple has kept it's promise of delivery in November for iPad iOS 4.2.
It looks like iOS 4.2 for iPad requires iTunes 10.1b.
iTunes 10.1 Beta 2, Mac OS X, 68.05MB
iTunes 10.1 Beta 2, Windows x86, 70.9MB
iOS 4.2 GM (iPhone 4), 624.27MB
iOS 4.2 GM (iPod Touch 4G), 608.65MB
GoldMaster” is software lingo for “finished”. Assuming that no horrible last minute discoveries occur, the GM is the same version that would be provided as Apple promised iOS 4 for the iPad in November.