improve my USB knowledge

[Rodrigo OSORIO (ros)]

Hi fellow hackers,

This weekend I try to increase my knowledge about USB devices - I start from 0 -
 playing with one of this funny low cost USB gadgets.
I read few articles about writing USB drivers, specially the Linux USB 
development guide, and I want to know if there is others (BSD related)
articles or documents I can/must read.  FYI, I work with the new USB stack in 8-CURRENT.

regards,
Rodrigo OSORIO