I've had the opportunity to make some updates to the freebsd-arm-tools.   If you're interested in trying FreeBSD-current on a Raspberry Pi, I've posted a build at which has full Wifi and pf support.  If you're interested, the kernel configuration is here.

Installing the FreeBSD on the Pi is simple.  Firstly, get an image, such as this one

Extract the Image

tar zxvf FreeBSD-HEAD-r249907-ARMv6-RPI-B-WIFI-4GB.img.tgz

Unmount the SD card

sudo diskutil unmount /dev/disk1s1

Burn the image to the SD card

sudo dd if=FreeBSD-HEAD-r249907-ARMv6-RPI-B-WIFI-4GB.img of=/dev/rdisk1 bs=1m

Unmount the SD again

sudo diskutil unmount /dev/disk1s1

Then, boot the Pi from the SD card.   ssh to root is disabled, however you can log in as username "pi" with password "raspberry", and su to root.