This program is awesome...
http://www.pidgin.im/about/
You can log into AIM, Yahoo, MS Messenger, G-Chat and the IBC Version of G-chat along with others) all at the same time on one program.
Oh, and it's free.
Pidgin
Having played with this program a little bit more now... I can honestly say it's even better than I initially thought.
Having AIM, G-Chat, Yahoo and IBC G-Chat all in the same window was a little imposing at first, I had at least 2 entries for each persona on my list. 3 or 4 for some. What you can do though, is group several ID's (such as an AIM and IBC G-Chat id) under one name (Like JP Starkey) and it appears as 'online' any time any one of those ID's is online. I also tacked an abbreviation on the end of every IBC member's 'group' name so that I don't forget which team they are (which happens quite a lot).
This way I run one program and don't have to worry about accidentally surfing away from a G-chat window (which I do all the time).
Having AIM, G-Chat, Yahoo and IBC G-Chat all in the same window was a little imposing at first, I had at least 2 entries for each persona on my list. 3 or 4 for some. What you can do though, is group several ID's (such as an AIM and IBC G-Chat id) under one name (Like JP Starkey) and it appears as 'online' any time any one of those ID's is online. I also tacked an abbreviation on the end of every IBC member's 'group' name so that I don't forget which team they are (which happens quite a lot).
This way I run one program and don't have to worry about accidentally surfing away from a G-chat window (which I do all the time).