Josh's iTunes Album Art Grabber is a pretty good resource for those of us who like getting their album art from one place. It's not perfect, but it's simple in both form and function, despite being tied to the iTunes Store at the same time it helps users free themselves from it.
Fire up the page and you're confronted by two dialog boxes, one for the artist name and one for the album name. There's not much leeway, though, so inaccuracies and typos won't get you very far. "Magnetic Fields" won't get you nuthin' but an error. "The Magnetic Fields," on the other hand, will make you swoon with joy. So when you do type in exactly what you want, the result is a high-quality album cover image, perfect for viewing on your newly discounted iPhone, other Apple-produced i-device, or--perish the thought--an i-less MP3 player.
However, if you're sure you haven't mistyped a single letter, Josh's Web site provides you with an alternative: go hunt down the album in the iTunes Store. This is a bit silly, because if you wanted the iTunes Store's album art in the first place, you would've just gotten it from there. You might as well go to the band's Web site and download the album art directly.
The other major problem I encountered is that the Art Grabber doesn't have the widest range of musicians listed. Sure, you can find the somewhat-obscure Kodo, but if you're looking for the better-known 126.96.36.199s, fuhgeddaboudit. There are so many variations on how to write their name that you might as well hand-draw what you think the album art should look like and scan it in yourself.