I discovered this song yesterday while listening to last FM.  It is a psychedelic classic rock song.  Click on the play button to listen to it.

Here are the lyrics:

There rides the rainbow demon
On his horse of crimson fire
Black shadows are following closely
On the heels of his desire

Ridin on in the mist of morning
No one dared to stand in his way
Possessed by some distant calling
Riding on through night and day

Rainbow demon
Pick up your heart and run
Rainbow demon
Lives for his sword and his gun