I use AllofMP3 (http://www.allofmp3.com) . They are based over in Germany and you put money in a account and download songs/albums from there site. The benefit of these guys is how they charge for downloads. By the byte... A average song, at 380k comp, will cost you about .11 and the entire album would be around $1.25. They all come to you in MP3 format and can be imported straight into iTunes for your POD.
Good luck...