At WWDC 2012, Apple SVP of iOS, Scott Forstall, announced one of the major new features of iOS 6 would be FaceTime over cellular. Introduced in iOS 4, FaceTime has been Wi-Fi only up until now, despite the widespread availability of 3G and 4G networks, and despite rival products like Skype having access to video of cellular for a long time now.
So the question becomes, will carriers allow it now?