Nice purchase Cereal! My most recent audio production pick-up was a midi controller of sorts, as well. It can be used as a midi controller, for PC, via built in mini usb port for usb-midi. BUT, even though it has no 'brain' or synth of it's own, and is just a controller, you can 'dock' your ipod touch or iphone, and use any number of different synth/music production apps, to lay down tracks on the go!
I bring this with me, a lot, when I don't wanna bring my laptop+controller, and just want my phone, but still have a controller.
http://www.akaipro.com/synthstation25
The action on the keys isn't amazing, but it really beats using the iphone's touch display. (which you can use at the same time as the synthstation, so as to extend the range, from 25 keys to 50.)