Apple and AT&T decided that it is a great idea to charge for FaceTime on the iPhone! If you have a grandfathered unlimited data plan, you will not be able to FaceTime over cellular network. iOS 6 beta builds did not enforce the restriction but iOS 6 GM build (Gold Master) wasted no time splashing this message when I tried using FaceTime. AT&T expects you to sign up for their mobile share option which is expensive if you have only a line or 2 in your account. I have an unlocked iPhone 4S and this showed up on my screen.
iOS 5 never supported FaceTime over cellular and with iOS 6, Apple officially supports it only if the carrier agrees to.
Not sure what FCC’s stance is on this matter but in our allocated quota of bandwidth, we shouldn’t be restricted on the usage of the data. This is pure daylight robbery. ‘iMessage’ was a serious blow to AT&T which stole away the SMS revenue and charging for FaceTime over 3G is a cheap attempt on AT&T’s part.