Netmeeting -
The Windows real-time collaboration and conferencing client is an easy to use Web phone as well as a tool for corporate productivity. It comes preinstalled on 95 to XP.

Trillian -
Grab the Best IM client available on the Internet today! Trillian .74 is completely free, with no spyware and no ads. 5 million downloads can't be wrong!

ICQ -
A standard in Internet chat.

Chat Files -
Chatfiles will give you an online chatroom for up to ten users. Ads will appear to defray the cost. $20.00 and the ads are gone.