A good IM web app for iPhone is TinyBuddy IM which is one of the top web apps on the Apple site and the link to the actual webapp is http://x.aim.com/ty/#_startPage
Now with the meebo the only problem I have is if I have to switch between screens in safari or even get a text message I lose my "connection" to the meebo. Is there a messenger online program that will allow connection to all three providers and allow it to be continuous?