AIM+ is an add-on to AOL's Instant Messenger for Windows.
It integrates automatically and flawlessly with AIM, adding crucial features like IM/Chat Logging (with an integrated History Browser), Ad Removal, Translucent Windows. AIM+ will not interfere with your AIM installation! You can still run AIM instead of AIM+, and you can upgrade to newer versions of AIM normally (w/o even re-installing AIM+). It integrates automatically and flawlessly with AIM, adding crucial features and options. And, of course, it's completely free.
News source: AIM+ Homepage
Download: AIM+