Stan wrote:

Is there another open-source product that does this? (combining separate apps to perform a larger task is very Unix-y, but phpbb and mailman are both fairly complex, so a single app that does both might be more useful).

mailman is actually very easy to administer and maintain, and is an ideal solution. In fact, anything with mailman integration is bound to be better than a product that tries to do all of that lifting by itself. I can't speak for phpbb, but I am happy with my mailman installation.