I will throw in a vote for http://vanillaforums.org/ if you need a free one.
Most forums and indeed web development methods are built so people that do not know HTML* but can otherwise extract something on a server and follow a few simple instructions can get something done. The trick however comes in knowing enough about databases to not completely hose it up once it starts to grow a bit and/or you want to add new features (wiki and forum logons the same and such).
*working is one thing, pretty/not obviously a stock theme is another and the latter will require some appreciation for HTML/CSS- not necessarily enough to make a page but appreciate what they do.
