The bulletin that is provided for this site is a good one. It's not free though. It's called
vBulletin.
There are a few bulletin sites out there that are free and decent.
http://www.freeforums.org is a good one for the free route.
The problem is that it's kind of hard to start out as a bulletin site unless you have a lot of people who are willing to help you market it. It won't be hit by a whole lot of search engines until there starts to be some content on it. It's usually to start with a website, gain traffic with that, and then once you have a lot of hits per day, then introduce the bulletin.
Just a thought.