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.
DutchPIPE allows Web developers to make virtual multi-user "avatar" environments. Each Web page becomes an abstracted environment or location where visitors and other items on the page are visualized. This status is retained as visitors move around. A lot of real-time interaction is possible, resulting in persistent interactive page environments. DutchPIPE uses AJAX and the DOM for the browser, and it works without Java, Flash, plugins, or firewall adjustments.
FleaIM is a Web-based MSN messenger clone. It can be used to register, sign in, automatically login. You can use it to modify your profile, state, and signature. It can send and receive messages, flash, and face icons. It can search, add, block, remove, and sort contacts. You can use it to view and download chatting history. It supports sound notifications for incoming messages, contact logging, etc. It can also maintain contact groups.