Last.fm Web Services
Huzzah! I was looking around the audioscrobbler.net web services and found my holy grail!
I've tried a bunch of ways to retrieve a cover for the most recent track. I've never been able to figure out Amazon's image naming system, though I found neat hacks at this cool site: https://aaugh.com/imageabuse.html that absorbed way too much time. I've also tried retrieving Google results and regex'ing the whole file, which was slow and rarely worked.
Well, today I found the artist info XML at audioscrobbler. Example I'm going to incorporate this bad boy into my last.fm scripts and put the system up here on the homepage. Maybe I'll try my hand at a WP plugin, just for the heck of it.