New iPhones and iPads will have a Video Chat Capability

These icons on the picture below were found by 9to5Mac in the 3.2 SDK. They seem to be a definitive evidence of video calling capability in future generations of Apple devices.

Searching for more evidence the source explored the code and also found a more direct mention of video chat in the telephony UI code:

And here is a reference to something called iChat:

So it is almost obvious Apple will bring video calling to their devices. But what will happen with 3G networks if millions of new iPhone users will start to make videocalls instead of common calls?