Check out this Java IRC multi-threaded applet. Features include private messaging, channel list and ban windows.

Download this minimalist multithreaded Java chat server for use with the chat client. Supports an admin client to remotely administer the server.

Browse this Java-based chat site that provides education and support for mental health issues. View the chats schedule and read the rules.

Allows you to place chat on your page easily. Able to be customized, and source is available to allow use with other networks.