How to get the latest sources:
svn --username anonsvn --password anonsvn \
      checkout svn://svn.turbocat.net/i4b
# The following commands will
# install the driver on FreeBSD 8:
cd i4b/trunk/i4b/FreeBSD.usb2
make S=../src all
make install

# NOTE: The driver is currently included in
# FreeBSD-8-current by default. 
# NOTE: Installing the new USB stack on
# FreeBSD-6/7 might require some manual
# patching.

More about the driver:
On this page you will find some short history about the new USB driver in FreeBSD 8. The USB driver was forked off the FreeBSD USB driver in 2004 and built up from scratch. The main motivation for this was to get the USB part of my ISDN driver working properly. Back then I was moving my ISDN driver out of the Giant lock and I realized that it was very difficult to get my ISDN driver out of Giant, as long as the USB driver did only support the Giant lock. This got me started looking at the USB code in the FreeBSD kernel. After 5 years of work a completely new USB stack has emerged with lots of new features and performance improvements. The size of the complete USB driver is around 30'000 lines of code, including comments.


The FreeBSD USB mailing list: freebsd-usb@freebsd.org
The FreeBSD USB wiki page: http://wiki.freebsd.org/USB