Marketplace
For anyone who used 37Signals Campfire. Not sure how long this is for free so grab it while you can.
✔ Works on iPad, iPhone and iPod Touch
✔ Simplified authentication: Sign in once and have all your rooms from all your sites in one place
✔ Streamlined message view: All the chat without the "enter / leave / kick / idle" message noise
✔ 37Signals account avatars
✔ Inline image previews
✔ Full sound message support
✔ Upload files from your Photo Library
✔ View previous chats with full Transcript support
✔ Tap a name in the campers list to start a quick @ reply
✔ Optimized experience: Version 3 was written from the ground up with performance in mind
Edit, this is the new v3.0 release and needs i0S 5.1 to run.
http://campfirenow.com/signup
It's a bit expensive for what it offers