Are you frustrated of registering if you want to load the CD covers with iTunes? Or are you looking for something else then the cover that iTunes finds? This might is your solution.
LastFMtoMP3 is a free Mac application that searchs on last.fm for the artist and album. If LastFMtoMP3 finds an image for the MP3 it adds it to the file.
Just drag the mp3 files into the table. Set up the popup button the way you like (overwrite or just add if needed) and push the sync button. Go for a cup of coffee and wait. That`s it!