Wouldn't iChat be more likely a 3.0 feature?
I don't know what the consensus odds are currently on iPhone hardware, but it would be a guess they might bring in iChat alongside a version 3 iPhone (likely to have video, better cam, and a small chance of front cam, which would be useful for video chat)...
It seems Apple's holding it's breath a bit (Mac mini, iMac, no bump for iPhone or Touch, ACDs etc) - so will they keep it on 2.2 till WWDC? I'd imagine we'd at least have some sort of leaked warning from multiple sources...