Chat
http://www.talk-n.com/chatindex.htm
Discus
http://www.chem.hope.edu/discus
ChatMachine
http://www.chatmachine.it/
DarkChat
http://www.calweb.com/~darkmoon/perl/darkchat.html
FruitChat
http://www.phonelosers.org/FruitWare/scripts.htm