Karl Fogel’s “Producing Open Source Software” is a well written and highly informative book (licenced under open copyright , naturally! ;)) delving into the human side of opensource development. It demystifies how successful projects operate, the expectations of users and developers as well as the culture of free software. Certainly a “must read” regardless if you are pondering how best to contribute to something like phpBB, starting out yourself, or better manage one you are currently developing for! :D