Actually the current 3G network is fast enough to handle iChat, AT&T simply doesn't feel confident their network could handle all of the simultaneous connections from iPhone users. Video chat was available back in the days of the 56k baud modem, really poor, none the less it was do-able.
I would really like to see video iChat become available on this model, though I doubt it will.
If I remember correctly 4G is capable of 150 MBs. I could be wrong as it's been ages since I last read a brief on 4G tech. Initially we should see 4G launching at 50 MBs and increasing at AT&T's pleasure.
WOW, that will awesome, I'm sad to find out that I was off on the 4G roll out dates!
So when do you think Apple will do the iChat thing? Next year? I mean AT&T's 3G network should be much faster and more stable by then, but when they go to 4G they will probably be scared while the 4G network is in its infancy too, so they have to pull the trigger some time. My bet is next year. Thoughts?