I've done just that - and spent hours playing around with it last night. It
only needs a sound-card, but also works in sync with Cubase or Cakewalk
etc. US$199 for the unrestricted version (the demo won't let you save your
songs) - much cheaper than the 2 303's and the 808 it emulates.
Even if you don't intend to buy the full version, the demo is damn good fun
(and you don't need any musical knowledge - just the groove in your soul).
I'll be sending my order as soon as I can sell my baby to get the $199 I need.
Marc.