Very nicely done work. As a developer with experience I would say that this is quite complicated implementation. It is not easy to integrate phpBB forum into WordPress template. Unfortunately not a lot of people understand the level of complexity. They do not understand the fact that website is hard work and expecting to have everything for granted.
jhong thank you for this plugin. I successfully implemented it on our website http://wpaam.com. Works great with minor issues which I hope you'll help me to resolve. But this is another conversation.
Keep working on it and think about payed either version or support.