Most songs will have id3, its a user supported song community, and to have it download as mp3
Apply this mod_rewite rule
Options +FollowSymLinks
RewriteEngine on
RewriteRule (.*)\.mp3$ /stream.php?songid=$1
and replace
echo "<a href=stream.php?songid=".$val[SongID].">Download</a><br><br><br> ";
in search.php, popular.php, and playlist.php with
echo "<a href=".$val[SongID].".mp3>Download</a><br><br><br> ";
If you make any changes to the code, just email me, and I will look at it, my email is on the google code site