With iChat not being amongst the features of the iPhone, folks looking to burn through some of that unlimited data via Instant Messaging might be interested in this neat little web-app: iPhoneChat.
You log in using your AIM credentials - however before account security becomes a concern, the author of the application states: "No data is logged, but all of your information does pass through my server.
I am not harvesting any information." There are a few known issues with the service - no buddy icons or groups, some rendering and scroll issues and it becoming a little awkward with more than 4 conversations open at once (IM junkies take note!) - and it seemed to work fairly well in testing. The main problem (and this is a server limitation as apparently it's rather resource intensive) is that sessions are limited to 10 minutes.
For those of you who just
have to have an AIM fix this might be an interim solution - however with iChat functionality being such a glaring omission from the handset, we'd hazard a guess and say it won't be long before we see improvements to iPhoneChat and perhaps a few other rivals offering a similar service.
The 'Read' link will take you to the app's homepage, but those of you wanting to dive in will want to go direct to the service
here.