I was able to make one iPhone 4 to PC Skype video call using Fring before Skype compatibility was pulled. It worked pretty decently too. I really hope skype can add this functionality in the future, at least over wifi.
I don't think any app developers want to pay for the expenses of managing servers needed to handle all the incoming data communications themselves. Any already-existing live video apps such as Skype/MSN (Microsoft probably won't do it), are perhaps in the process of making this happen. *crosses fingers*
When I heard about this feature prior to iphone release I was excited. I was hoping it would work with a mac's ichat. Unfortunately not the case.
Their was a rumor that came out last month that has me interested, although the rumor was that it was going to be released last week, I still think this will happen soon. I would like to think that Apple is going to release a Desktop FaceTime application to replace iChat.