One of the biggest disappointments of the new FaceTime video conferencing feature on the iPhone 4 is the limitation to Wi-Fi - but now there is an app for that.
Fring for iPhone has just added 2 way video-calling that also works over 3G. On top of that you can video call your non iPhone friends as Fring is also available on Droid and Nokia Symbian S60 phones.
Watch a demonstration of the 2 way video call on the iPhone 4 below. It remains to be seen if carriers will start to complain about this. More details on the Fring blog. Via MacRumors.