M was stuck in a rather, for the lack of a better word, tightass network. So to facilitate communications, I wrote mChat in php. It grew from a simple (and rather smugly) script into one that supports avatars from atomicmpc with auto refresh, /me and user highlighting.
Try it out, there is almost always some one there. If you are interested it using the script on your site, just drop me a line.
Cheers,
Steve