It's okay Mark, you're not the only one.
From the main page of the message boards where you see the categories (General Discussion, Lost and Found, etc.), click on the category you want to start a new topic in, say General Discussion. There will be a button that says New Topic.
I think the reason the New Topic button doesn't show up all over the place is to encourage people to post in the correct category. Not so critical for smaller sites like ours... but I've seen people take it seriously at bigger sites.
Oh, and hey, I got you listed as a member now. Sorry about that, I have to assign that manually and am just kind of catching people as I go.