And believe it or not...if you download a song from the iTunes store, you can just right click on it while it is in your library and choose the option "Create MP3 Version".
Not the best idea considering you are taking one compressed format and converting it to another compressed format.
and you get to keep 10 songs a month. so technically ur only paying $5 a month to rent unlimited amount of music..which you can delete if u dont like.