While Apple’s touting its webcam-based video chatting standards for FaceTime WiFi-only video chat on the iPhone 4, the main feature that users should know is that FaceTime essentially routes your call seamlessly over the Internet as a VOiP call when activated. That means that once you initiate a FaceTime chat, your voice call will also be routed over WiFi so you don’t use up your minutes. You do have to still initiate your call on AT&T’s network with AT&T and WiFi radio reception. Then, once the call starts, you can hit the FaceTime button–provided your other party possesses a device that’s capable of FaceTime, which at this time is limited to the iPhone 4–and then once FaceTime connects, you stop using your AT&T voice minutes and Apple’s VOiP protocol kicks in.
Let the rollovers begin for those saved unused AT&T minutes. Now, if the carrier can be a bit more generous on its data portion, it’d be awesome!