http://www.icq.com
2. AOL Instant Messenger
http://www.aol.com
3. MSN Messenger Service
http://www.msn.com
4. Cahoots
http://www.cahoots.com
5. Yahoo Messenger
http://www.yahoo.com
6. PowWow
http://www.tribal.com
7. Firetalk
http://www.firetalk.com
8. PeopleLink
http://www.peoplelink.com
9. ichat Pager
http://www.ichat.com
10. ScreenFIRE
http://www.screenfire.com