I'd strongly suggest looking at one of the hosted solutions instead of trying to run up your own box for something like this. There are companies that make this process pretty easy.
I'm not sure if RackSpace (the company that hosts dbforums.com) provides this service, but if they do I'd recommend them. I'm actually looking at using them to host one of the semi-public boards that I do the geek-grunt work for as a test to see if I want to move more of them when the current contracts expire. I've got a sales contact now, and expect to have some tech contacts in the next 30-45 days or so.
The companies that provide this kind of hosting service basically give you free use of their servers and bandwidth, and sometimes even throw in storage if you generate enough traffic. They then sell the advertising rights to recover their costs.
Be careful to read the fine print though, since some of the companies claim the right to use any material posted as they see fit (you surrender copyright, etc to all material posted). This is a VERY bad thing! Avoid it like the plague.
If you have enough cash to get started (usually well under $1000), you can also do this on your own. You basically lease out the server, buy the software, arrange for the advertising, and manage the box yourself. This is a bit more work and requires some cash up front, but then you own all of the content in every way, shape, and form. It can also become a pretty decent money-maker too, assuming you get some click-through on the ads (in a frat this is pretty likely if you can control the advertisers and encourage your brothers to investigate the advertisers). Aside from making some money for your house, you get some great experience to post on your resumé!
-PatP