Yes. I have one computer where I boot WinNT4, Win2000, Win98 on the first HD. Then on the second HD I boot, FBSD6-3, FBSD6-4, and I been thinking also about getting FBSD7-0 going on it too. You are allowed 4 Primary partitions on a hard drive, and you can put an OS on each of them. Usually though, one of those partition is used for an extended partition per hard drive (but could boot 4 if you make them all primary). You will need a boot manager. I used the Patition magic boot manager but FBSD provides one that I have never had a problem with. I use it on my laptop because Parition Magic requires Win98 or a NT version in FAT. I use Partition Magic 5 and 8. I never install partition magic 8 to the HD because I had a problem once and never tried it again. I use 8 to boot from the CD, and use 5 inside of Win NT4 (which in opinion is the only decent Windows ever made). Never install partition magic 5 in win98; it gets caught in a loop. Silliest thing you ever saw. Watch out for (can't remember right now) boot sector code i.e. at the beginning of the HD that tells where to boot. The format sys stuff. In other words you should be able to deactivate the boot manager, set a partition active, and boot to it (most of the time 2GB limit no problem on newer OS).
So to answer your question. If it is a blank HD, just install FBSD and install the boot manager. If there is other stuff on it, then you will need something like PMagic. Can be done; been doing it for years.
I have had a problem after installing FBSD though. When I install FBSD, and then go into PAMGIC, it complains about incorrect geometry. I just click go ahead and fix then all of my OSs are happy.
