ARSC Really Simple Chat
- A webchat software written in PHP and MySQL. It is compatible with every browser known today, even text-based ones. [Open source, GPL]
- http://old.manuel.kiessling.net/projects/software/arsc/

Chatty
- A nice script that lets create a simple chat in a few minutes. Requires MySQL. [Open source, GPL]
- http://www.olivo.net/software/chatty/

BlaB! Lite
- (formerly SimpleChat!) Fast, reliable, XHTML compatible web chat written in PHP and JavaScript.
- http://hot-things.net/blab_lite.php

X7 Chat
- A PHP chat script with unlimited users, rooms, and messages, IRC style commands, full message formating. [Freeware]
- http://www.x7chat.com/

Open Chat
- Features include unlimited and private channels; moderators, whisper mode, timed sessions and multiple language support.
- http://phpopenchat.org/

Wollabot
- Modular service bot for IRC channels.
- http://sourceforge.net/projects/wollabot/

Webfroot Shoutbox
- Allows users to post little blurbs on your website like a small guestbook/chat box. Inline or IFRAME, powered by mySQL.
- http://sourceforge.net/projects/shoutbox/

WebChat
- A chat application that features multiple rooms, no browser refresh, database back-end, emotions, private messages, and multiple language support.
- http://www.webdev.ro/products/webchat/index.php