Nice little app here. It written in PHP4 with some nice AJAX sprinkled over it for effect.

YShout is a lightweight package that allows you to easily add a shoutbox to your website. Shoutboxes are a great tool to receive feedback from your visitors, and YShout allows you to chat with them in real-time! YShout is also:

Think of it as a basic version of Campfire written in PHP rather than Ruby.