php Free Chat is a simple, fast, and customizable chat server that uses the filesystem for message and nickname storage. It uses AJAX to smoothly refresh and display the chat zone and the nickname zone. It supports customized CSS stylesheets and a plugin system that allows you to write your own storage routines.
The SeaMonkey project is a community effort to develop an all-in-one Internet application suite. It contains an Internet browser, email and newsgroup client with an included Web feed reader, HTML editor, IRC chat, and Web development tools, and is sure to appeal to advanced users, Web developers, and corporate users. It uses much of the Mozilla source code powering such successful siblings as Firefox, Thunderbird, Camino, Sunbird, and Miro.