it will load dynamic mp3's heres an example
http://smokeycash.com/mat/
you download the swf
http://smokeycash.com/mat/mat.swf then place it in a directory with 10 mp3's named track01.mp3 thru track10.mp3
the demo i made just has 1 track in the directory so only #1 will work..
p.s. it streams the mp3 so it will play before it finished downloading