A few weeks ago a friend referred me to pandora.com, which allows you to listed to music, commercial free. The key is that you pick out artists and/or genres that you like and Pandora creates a radio station for you based on your preferences.
Pandora does have some limitations. You can not save the songs, but you can order them, and you can not back up and listed to the song again. The music just keeps coming and coming. You can even mark songs that you like and ones you don’t like. You can skip songs too, but only a few during a set period of time.
It’s free and the quality is very good. Check it out.