I think you're going to need to sign up with a dynamic dns service to get the domain to point to your server. Then you can either go the WAMP or the LAMP route depending on whether you want linux or windows. Then pirate bulletin from a place like vbteam.info (currently down).
Go LAMPP if you can. WAMPP and XAMPP both have security holes. If you don't mind pirating software, pick up a copy of Vbulitin. It's really the industry standard. Failing that phpBB is the best free product out there.
You should fork over the $10 bucks for a domain, but if you're running everything off your own servers, your only expense is going to be electricity.