Sorry if this is old news, but I just found out (totally by accident) that Gmail Chat is now interoperable with AIM!
To sign into your AIM account up while in Gmail Chat just click on the “options” button under the Gmail chat box and then login to your AIM account. You will now be able to chat with your Gmail Chat or AIM buddies. Your AIM buddies are distinguishable from your Gmail buddies by the little AIM icon next to each AIM buddy!
Yay, No more having to deal with that over-bloated AIM adware application ever again!