pretty cool one i found recently is "Now Playing in iTunes". it displays the artist and track you're currently listening to as your online status in iChat. i got it over at http://www.macscripter.net
awesome site with a great discussion board too. i've also made a few of my own, droplets for encoding at different bit rates.
Fetch Art for iTunes is a small program that will fetch album art for one or more songs using Amazon's XML interface, allow you to preview the art that was found, and add the art you want to iTunes. The program is controlled through the iTunes Script menu: once it is installed, album art can be downloaded by selecting one or more songs in iTunes and choosing "Fetch Art" from the Script menu.