Ok, found out how to do it. I want MP3's because the interface to my stereo uses only mp3's.
First, hymn, http://hymn-project.org/ goes from m4p to m4a (mp4).
faad, http://www.audiocoding.com/modules/mydownloads/, mp4 to wav
lame, http://lame.sourceforge.net/, wav to mp3.