Matt Cutts wrote a series of blog posts outlining the general approach of reverse-engineering a USB device and getting it working with linux, and explaining how he did this for a USB controlled toy missile launcher. You may find them a useful starting point.

 - http://www.mattcutts.com/blog/reverse-engineering-a-windows-usb-driver/
 - http://www.mattcutts.com/blog/playing-with-a-usb-missile-launcher/
 - http://www.mattcutts.com/blog/linux-usb-device-driver-info/
 - http://www.mattcutts.com/blog/compile-a-simple-usb-program-in-linux/