I just came across the AOL/AIM gadget today, and I did have some buggy issues with it, so be warned that it may not work perfectly.
First, you’ll need to install the gadget from here.
Once you’ve installed it, right-click on the sidebar, and choose Add Gadgets. You should see the icon in the list:
Double-click on the icon, and it will add itself to the sidebar. You can then login and see something similar to this:
Note that I took this image off the official site. Hopefully that’s ok… I didn’t really want to show my own screenname, and blurring the picture seemed to take away from the illustration effect.
I’m assuming that this gadget will get better over time, since it’s a beta release right now.
Updated article to point to new location. Thanks Will !