[joeminkie]

You don't have to be on the _same_ wifi network, you just both have to be on wifi somewhere. It's like video chatting on the desktop (Skype, iChat) but on the iPhone instead. I'm sure they were forced to make it wifi for now because the 3G carriers couldn't handle all the extra traffic (AT&T at least).

[iworkforthem]

Hm.. correct me if I am wrong, let's say I call someone I know via the AT&T network on the iPhone 4, with FaceTime will be able to see the other person, providing there is wifi connection someone near me n the person I am calling. Cause FaceTime is providing the video chat feature via wifi over the Internet instead of the 3G carrier.. Right?