[michaelbuckbee]

Since Facetime is running SIP over WiFi, does AT&T still charge you minutes for a Facetime call or is that only for the non-facetime portion of the phonecall?

[mattparcher]

Apparently no:

“The voice call ends as soon as the FaceTime call connects... the FaceTime call is over Wi-Fi so does not use carrier minutes.”

http://news.cnet.com/8301-13579_3-20008289-37.html