Just installed FreeBSD 8 on a spare partition of my computer. Was planning to use the Debian-installed GRUB to boot it, but when I went to edit GRUB config files they had changed beyond recognition. GRUB 2, it seems, is very different to GRUB 1 More here
Make sure you edit the root parameter to the partition where you installed FreeBSD. Remember that “real” partitions are numbered 0,1.. and UFS partitions go a,b.. and you need both.