Managing a large digital music library can be tricky. Often the album art is missing - and it can be hard to track it down and drop the right image in to your music management tool of chouice. Some, like iTunes, will download images from their associated stores - but they're by their very nature limited to what's in stock. The result is a significant proportion of the library without any cover art.
This afternoon I found a useful tool in the shape of AlbumArt. It's a very basic service that's nothing more than an album art search engine. It's generally accurate, and very easy to use. The only things it's had trouble with so far have been self-issued albums by bands like Marillion, magazine cover CDs, and some compilation albums (which is probably more down to my initial data entry than anything else!).