Snailmix is a project I started in November of 1997, and ended April 6, 1998. It is an S3M loader and player for DJGPP. It also plays voc files for sound. So just get MIDAS (in my link section), its quality is better (it does interpolation) and it loads XM as well. I can proudly say I got some of the S3M effects a lot better than MIDAS implementation, and plays lots of songs without any bugs. (MIDAS is weird with some S3M's).
SnailMix Download Locations
You will need the Allegro library to compile any this.