Fantastic program i bought off of Steam over the weekend, it will convert 90% of your music tracks (It doesn't support DRM protected files yet ) and turn them into a little rollercoaster based on the song's data.

Well worth trying the demo, but seeing as the game is only $10 (A shade over a fiver at the moment) it's a massive bargain.

http://www.audio-surf.com/

It can cope with almost any song you throw at it as well:
http://www.youtube.com/watch?v=2EsVyEnhxWY Blur, Song 2
http://www.youtube.com/watch?v=h4fltqbOxbE Dragonforce, Through The Fire And Flames
http://www.youtube.com/watch?v-EfA6G1o8A Moby, 1000

Works well with slower tracks as well, like Pink Floyd's Echoes.

Definately check it out, very addictive!