phpBB3 is released last month. I upgraded one phpBB 2.0.22 to phpBB 3 yesterday.
I will show you the details about the upgrade later. Now I just mark some good features phpBB 3 added.
UTF-8 Support, Search Engine spider Handling, Set min/max Username Length, Set min/max Password Length, Set Password Complexity Requirements, Attachments, Post Drafts, Memberlist Searching, Disallow Non-Registered User Memberlist Viewing, and also a lot of other new features.
The completed feature comparation between phpBB2 and phpBB3.
The comparation of phpBB to IPB, VB, and SMF is here.
Download phpBB 2 or phpBB 3 here.