Hi,
Recently we did some experiments with PICkit 2 (PICkit 2 is small size device with USB connection).
We did not have any USB board in our hands and we had to try to use PICkit 2 as demo device.
Now we created article about that experiments.
May be it would be useful for beginners, who want to create USB connection to their robots, based on USB PICs (PIC18F2550, PIC18F4550, etc.)
URL:
http://www.RoboHobby.com/pickit_2_as_usb_demo_board.jsp.