This was exactly what I needed for my Zaurus SL-C860, which is currently acting as a mobile access point. The storage of the system is limited, and I was looking for a quick, simple chat system that allowed people to connect with a minimum of fuss, and chat with as little delay between replies as possible.
Chat-N-Time has good documentation and the scripts are commented by the author, clearly showing what is going on and how to configure it. I made extensive changes to my version - to support CSS - and I haven't quite finished yet, but it's fun looking through the script, figuring out how it works. The best thing is all it needs is a web server and Perl - there's no need for SQL and no Java applets required. I would recommend Chat-N-Time to anyone wanting to set-up a small chat system on old hardware, or embedded devices.