I'm looking for a good messenger app for the iphone that doesn't have to be free, but free is better than paid.

My main requirement is that it has a desktop (or web based) counterpart that integrates with the iPhone app so that I don't have to log out of one to log into the other.

I've been using Meebo since I got the iPhone but Meebo's online service is lacking in a few features (but I can deal with that) the most annoying thing is that it logs me off the online version to log into the app (but only sometimes) other times it does just what I want and works in both places at the same time. Though usually I'm having to send a 1 to AIM!!!!!

If only Digsby made an app!