From Complete Messenger:
Complete Messenger is a free instant messenger designed to support all currently available messaging protocols. With its convenient interface you don't need to setup several applications to chat with friends using different instant messengers. Complete Messenger supports following popular protocols: Oscar (ICQ protocol), MSN, AOL, IRC, Yahoo, Jabber. Customizable settings allows you to setup all your different instant messenger accounts in a few minutes and then you can start chatting with all your friends easily and conveniently.