Rad, Quiet Earth has a good how-to on listening in to what’s going on over USB, great for reverse engineering weird USB doo-dads… – “This is intended to be a howto to debug usb transactions under linux, or simply to reverse engineer propietary usb stuff. If you need to reverse engineer a windows only usb driver, you can do it easily running vmware under linux. We can snoop the usb traffic from windows using usbmon which is part of the linux kernel since version 2.6.11 (I think). Previous to that you had to use patches.” – Link.
USB Snooping in linux