iChartwork fills in the gaps that GimmeSomeTune leaves out. It installs itself as a simple Preference Pane (pictured above) and lets you choose whether you'd like it to integrate into Adium or iChat or both. The basic functionality of the software is that it sets the currently playing song's Cover Art image as your display picture in either or both of the aforementioned instant messaging clients. Very nifty. Also, unlike GimmeSomeTune, it does not launch either application if it is not open already. It is again customizable to just the right degree - it lets you choose two different pictures for scenario A when you don't have a Covert Art image for a particular song and scenario B when you're not playing songs, unlike GimmeSomeTune which leaves the last-played song's Cover Art image hanging there if you just quit iTunes.
Simple. Elegant. Beautiful.