The topic says it all. If you don't know what tracker music is, it's sort of like Midi, uses tracks and same sound waves to create the music BUT tracker stores the waves in it's self, so it sounds the same on any computer. It also sounds much better than midi, depending on who made the waves and how there used.
Here are some links if you want to try some of the music:
www.modarchive.com --> Probably the best place to get tracker music
www.modplug.com --> Good place to find software to create, and play tracker music back
You can also use WinAmp to play the music, but the plug-in for it doesn't sound very good. ModPlug Player or ModPlug Tracker (on the ModPlug website) are recommened.