Within any message board, there is a "new topic" link at the top of the page. Simply click this link and you'll be presented with the entry form. Just enter your new topic's title, along with the content of your topic, and hit the "post" button when you're ready.
We welcome a wide variety of topic discussions on our boards -- however, please try searching for a topic before creating a new one. It's possible another thread that deals with your topic has already been started.