I have Ubuntu 10.04 installed as my primary operating system, and I installed PC BSD in a different partition: /dev/sda4 without installing it's boot loader. I figured out that I need to edit /etc/grub.d/40_custom to add an entry for PC-BSD. So far, nothing seems to work, though.EDIT: this sort of works, but doesn't fully boot the OS, it then asks me for the MOUNTROOT partition.menuentry PC-BSD 8.1 {    insmod ufs2    set root=(hd0,4)    kfreebsd /boot/kernel/kernel}The selected answer below is correct. If you are dual-booting with Linux I suggest NOT installing the PC-BSD bootloader as the documentation suggests, unless you enjoy pain.
How do I add PC BSD / FreeBSD to Grub 2 boot loader?
boot;freebsd;dual boot;grub2
this is what I have in /etc/grub.d/40_custom. Works for me :) Just remember to subsitude hd0,3 with your correct entrymenuentry 'FreeBSD 8.0 64bit' --class os {    set root='(hd0,3)'    chainloader +1}