I have built this device, and despite i have not got my new car yet (will be ready in a few days) it seems to work.
It's a similar construction, and it works perfect. You can see the Documentation for it, it uses an Virtual serial port over USB to communicate - should be pretty easy to program an application for it!
http://www.mictronics.de/?page=can_bus
My friend Henri built the interface, and done some changes, my interface is 100% the same as his, you can have a look here:
http://www.skippari.net/projects/can-usb-interface/
Regards, Per.