A good source of information about using FreeBSD on the Raspberry Pi is the 'Embedded Computing' section of the FreeBSD forums. If you have any questions, that's probably the best place to ask them too:

http://forums.freebsd.org/viewforum.php?f=11

FreeBSD now also supports several other popular ARM development boards besides the RPi: Wandboard, BeagleBoard, SheevaPlug, etc.