Windows media player would do the trick on your computer
(Edit: noticed glp mentioned it, but here is how)
I don't use it to play mp3s but since everyone who isn't an apple user has it, works great for being included free.
Start menu, Programs --> windows media player
while the file is playing, go to view and then enhancements. Select show in enhancments. Click till ' playspeed settings' shows up..
Adjust the bar...faster or slower....
for Ipod do what GLP said - but it sucks it only does it so much faster - not worth the hassle of converting the file.