When updated itunes, I saw this message before installation...
What's new in iTunes 10.1 (64-bit)
Use AirPlay to instantly and wirelessly stream videos from iTunes to the all-new Apple TV.
Sync with your iPhone, iPad, or iPod touch with iOS 4.2.
Provides a number of important stability and performance improvements.
I have not updated an iphone with it yet, but I am assuming that it will update it with iOS 4.2. May be is just staging for 4.2. I don't know. I could try connecting my iphone with it and see if says to update it, but then again, I don't really want to take a chance
I downloaded new iTunes 10.1 and hooked my iPhone 4.1 basebend 02.10.04. Clicked on check for updates and iTunes stated you have the most upto date version(4.1). So no 4.2 release as of yet.
I think they are going to release iOS 4.2 a day or two before thanksgiving and the unlock will be out by thanksgiving so we will be giving thanks to apple and unlockers at the dinner table