First off, AIM is free to users, but not to maintain. AOL has to pay for their servers, ongoing development, etc. Theoretically these costs are subsidized by advertising.
Secondly, modifying AIM to block the ads is a violation of your user agreement.
Thirdly, believe-it-or-not, AOL
does provide an ad-free version of AIM. It's a Java version called
AIM Express. It runs on Windows, Mac 8.5 and up, Linux, and any other operating system that supports JDK 1.1.
That said, you have a couple of ethical options. You can choose to ignore the ads, or you can use another instant messenger that doesn't use ads.
There are a lot of ad-free options on the Windows platform (Trillian, Imici, Jabber, even Sametime). On the Mac side, I'd recommend one of the Jabber clients (
http://www.jabbercentral.org/clients/).
Jeff Hester
BigBlueBall.com