I don't have the album art for most of my music, and I don't have time to go find and download images for all of my album. Any suggestions?
I don't know if it's the easiest way, but I use Media Monkey. It goes to Amazon (you choose which nationality) and auto-tags what it finds. Just click on the album and hit Ctrl+L.
My Classical music is the most problematic, but I find amazon.ca pretty good track listings.
Try Tag & Rename. It has built-in Amazon lookup that will download cover art and save it to folder.jpg or directly in the music files as part of the ID3V2 tag.
I use mp3tag for Windows XP. It links to Amazon and Discogs for the album art.
I use Album Art Downloader. It's open source and written in .Net 3.5. To use it you simply point it at a directory and it will search for cover art for all albums within from a variety of sources.
I would checkout Songbird, with the add-on of Album Art Manager.
Songbird is an Open Source project, and has feature rich media control and organization.
I use TuneUp. It's paid for, but it can get album art and fix all the metadata for your library, super-simple.
I use TagScanner, it does all the job, from find the artwork and update de ID3 stuff to renaming the files.