Apple at the WWDC 2010, announced the Apple iPhone4 and its awesome features, one of which included the new Application called as FaceTime which is going to revolutionize the whole world. The biggest drawback with this feature is that this works currently only in the Wifi Environment and when two iPhone4 devices are in the same wifi zone.
This feature allows you to have a Video chat both in Portrait and Landscape mode in HD quality, something which is not available in any Smartphone yet. Apple plans to make the FaceTime an open standard which others can use.
Just buy the new Apple iPhone and get this video calling feature which automatically swaps the front and back camera while you on the Facetime. May be in the future they would add the functionality to use this feature over 3G or any Cellular network.