A form to do what? The HTML portion is quite straight forward, and if you only need a backend that sends the contents to a specified email address, there ought to be ready-made scripts for you to install. Besides, there are plenty of programming languages for writing a form backend. Perhaps ASP (.NET) and PHP are the more common though.
ProBoards on the other hand, don't they offer independent forums? Of course, a forum consists of a lot of forms, i.e. the text editor. Confusion of terms galore.