I think this is a likely integration to happen. iMessage is a very useful app, it’s one of the great apps of iOS5. The Styling is basically the same as iChat for OSX with a lot of the same features. When the other person types you can see that they are about to send a message, as well as delivered times.
Another feature that makes iMessage so useful is that it auto updates your conversations on as many devices as you are signed in on. For instance, if you are talking on your iPad with your friend, but then you leave and use your iphone, all your chat history is there and you don’t miss a beat.
If Apple were to do this it would be one of the first non IM apps that would let you chat between a computer and the iPhone.
Would you use this feature if Apple made iChat compatible with iMessage?