FaceTime, the video-calling feature that Apple first unveiled for iOS in 2010, had previously worked only with a Wi-Fi connection. However, with iOS 6, the service is expected to expand to cellular as well.
When it does, those iDevice customers using the service by this method will naturally use more data.
For AT&T customers, that data could cost extra. At least this is what we can surmise thanks to a new message uncovered in iOS 6 Beta 3.
After resetting network settings on an AT&T iPhone powered by the latest beta, you'll see the following message when attempting to activate FaceTime over cellular.
Currently, AT&T plans that include the iOS Personal Hotspot feature start at $50 per month. While AT&T has yet to announce FaceTime for cellular pricing (or even admit there will be an extra charge), the company did provide this comment:
We're working closely with Apple on the new developer build of iOS 6, and we'll share more information with our customers as it becomes available.