This should do the trick for you
http://www.sharewareconnection.com/d...ter-14716.html
i cant test it out for you as i dont have an AAC file
or
iTunes will convert UNPROTECTED AAC to MP3 files. Just set MP3 as the import preference, then the "Advanced" menu will show "convert selection to MP3" (or whatever the import selection is set to).
or
http://hymn-project.org/
or
http://www.soft32.com/download-mirrors-25214-8.html
The last one definately works as ive tried it, Its UFONY 1.2