Dual Boot with Free BSD

I have UBUNTU Intrepid 8.10 as my main boot and operating system, however I thought I would try out the Free BSD system as a secondary experimental system. I also have Virtual Box installed - so I thought I would try this DSD on Virtual Box. No such luck it will not install on a Virtual Machine.I therefore have no option but to go for DUAL BOOT. My question is-considering NOT wanting to disturb my UBUNTU configuration, how do I go about partitioning and installing BSD as a secondary system.If possible I might add Windows XP on to the list as well. Then I can get rid of Virtual Box which has so many operational limitations !):P