If you’re running Drupal on a Web site and want to integrate chat software, check out the phpFreeChat module, which integrates the standalone phpFreeChat program into Drupal 5.x. I’m the current maintainer of this module, and just uploaded v1.3.
There’s a copy of the phpFreeChat module on my own Web site because I shared it from there while I figured out CVS, and don’t want to break the link. There’s also a phpFreeChat-compatible theme on my site that I haven’t uploaded to Drupal yet.
phpFreeChat is a great program (I added an “away” feature in the Drupal version), but has a limitation that may be a problem for some people: it conflicts with jquery if it’s on the same page. For most people this isn’t an issue, but if it is for you, you can use FlashChat – another feature-rich chat. I figured out how to integrate this with Drupal 5.x, and will post the configuration file and instructions shortly.