I host this site as well as mnmazda.com. Basically you need a working knowledge of how to
-use an ftp server to upload and download files to create a www site
-mysql configuration & setup
-register a domain name
-choose a forum software to use. This site uses vBulletin, there are many others out there. I recommend one called Simple Machines, its free and pretty kick ass.
-after all that, you need to be preparied to maintain the forum. Install updates regularly, maintain your userbase, and basiclaly figure out how to not waste *all* of your time on it
You can either learn how to do all of this yourself, or pay someone else to do the setup stuff and then you handle the rest. If you need help, I know a guy
pm me for info.