The forthcoming iOS 6 update will allow FaceTime over cellular networks.
5er driver said:As an experiment, I just FaceTimed my iPad3 with my iPhone 4s, both on the same wifi, and it works. You'll get some audio feedback if the devices are too close though.
So, you can FaceTime yourself.
Sent from my iPhone 4S or iPad 3rd gen, whichever I happened to have in my hands at the time, using iPF.net