I have uploaded them to the site. You can access them here.
M3U is not a music file, its just a playlist file that indicates the name of the song and where it starts and ends.
The music itself is in the .sgc file.
Try installing foobar2000 or Winamp, and the Game Emu Player or NEZPlug/NEZplug+ plugins respectively.
Also, you can get some MP3s here:
http://downloads.khinsider.com/game-soundtracks/album/castle-of-illusion-mega-drive-rip-
Though I'm not sure if that's the version you want.
NEZPlug definitely still works in the current version of Winamp, it's what I currently use. You have to make sure you go to "file types" in the preferences menu and make sure that KSS is selected.
Alternatively, once that plugin is loaded, the M3U file should load all of the associated KSS files directly into Winamp (provided that they are all in the same directory as the M3U file).
NEZPlug definitely still works in the current version of Winamp, it's what I currently use. You have to make sure you go to "file types" in the preferences menu and make sure that KSS is selected.
Alternatively, once that plugin is loaded, the M3U file should load all of the associated KSS files directly into Winamp (provided that they are all in the same directory as the M3U file).
Oh wow, I just realized that the site I grabbed them from totally changed their format a short while ago. I don't like that.
Anyway, I uploaded the file from my personal collection. Give it a shot now.