I personally can't wait until the final release of this FREE forum software. I currently use phpBB2 and well it lacks in many departments but hey you dont have to pay for it.
I have installed a beta version of phpBB3 and messed around with it a bit, let me tell you a lot has changed. The whole administration side is prety much completely overhauled and it is for the better. I found that after a few minutes of messing around I was able to do so much more and with much less effort than in phpBB2. Things like admin rights, moderation, permission settings for forums are so much easier to do. The entire structure of how the forum is organized has also been changed and again after a few minutes was amazed at how much better it was. For example instead of spending 6-8 hours of hacking (scripting additions) to the forum to add sub categories all you have to do is make one. Yeah that is right they finally added this to the app.
Anyways have a look over at there forums and if anyone wants to test out a beta version PM me and I can give you login details for the one I set up.
http://www.phpbb.com/development/ - dev site
http://www.phpbb.com/phpBB/viewforum.php?f=46 - beta support forum