How to make 3G Video Calls?
There is currently no way to do this, unless the device manufacturer has added this into their ROM's.

This isn't available in any custom ROM, and the implementation of it in Android is somewhat limited, and far from complete.

I believe that Google decided that as they are using an Android, they would have large internet bundles, and therefore it would be cheaper to use internet video calling, so they haven't been implementing 3G video calling (at least not at any great speed).