Sorry to take this slightly off-topic, but with forum software, you get what you pay for. It could mean the difference between the success and failure of your forum.
I know personally I wouldn't generally join a phpBB forum, because it seems like the owner hasn't invested any money into it, therefore isn't bothered about it.
If you
really do have to use free software, use SMF. But as I say, with all free forum softwares there's usually a lot of security holes.
Best of luck.