You can do a lot of neat things with iTunes beyond organising and playing music. Brian Tong at CNET demonstrates how to create and print custom, mosaic-style covers for My Awesome Mix CD.
It doesn't involve any add-ons or graphical trickery—just a standard copy of iTunes and making sure you've got album art for your music tracks. Once that's done, you can pretty easily make a mix and create a custom cover for it:
We dig getting to re-discover the little features that get overlooked in otherwise well-covered software like iTunes. This one has been around since at least 2004, but doesn't seem to have gotten its own mention. Print your own CD cover in iTunes [CNET | The Download Blog]