Finishing touches are being added to the next incarnation of Apple’s mobile operating system, iOS6. One of the features people are excited about has to do with the video-chat app FaceTime, which currently works only on Wi-Fi networks. With the update, however, FaceTimers will be able to see each other over 3G networks (gobbling up data while doing so).

Reports are coming out today that AT&T may want to charge extra, if people want to use the app on its network. People over at the Apple geek blog 9to5Mac have been playing around with a beta version of iOS6 and posted a picture of the error message they got when trying to make a 3G FaceTime call. The message reads: “To enable FaceTime over cellular on this account, contact AT&T at 611 or http://www.att.com/mywireless.” This is the same message that appears when you try to set up an AT&T Personal Hotspot, a service for which the company charges extra.

According to 9to5Mac: “We attempted to bring up the same error message when enabling the FaceTime over Cellular feature on a Verizon iPad Wi-Fi + Cellular, but the feature enabled without an issue.”