Album Art Downloader: http://sourceforge.net/projects/album-art/
My parents have a bucket load of audio CD's, and they have never ripped any of them. EVER. They don't listen to said music on CD either anymore, probably because of the nuisance created by having to search for a particular album when you don't even remember what you have.
Come on now, people. MP3's are not
a new tech. My mom does download songs from iTunes or Amazon, but I took 90+ discs home with me to rip and (properly) tag the files for them knowing full well that they do have more music than this (ie. there are other albums I remember listening to as a kid that I didn't find yet to rip, such as the 1989 Batman film score). It's just a waste for them to have bought all this music and never use it.
I'm using four resources to do this: WinAmp Pro, Mp3tag, Album Art Downloader, and Google. I would use Google alone to search for my own album art, but some of my parents stuff is rather obscure and I need all the help I can get with them.