Vanilla Forums

Vanilla Forums is an open source self hosted forum software as well as a paid hosted option. It has become a popular community software application as it has concentrated on the core of its business as a community software application. It is a Canadian company and was voted as the top forum software application by CMS critic.
Some popular examples of companies using Vanilla for their community include, Thexyz.
Getting started with Vanilla Forums
You can download the package and install it on your domain for free. It has a simple installer process and requires a MySQL database. There is also a very well put together migration tool of you are coming from another forum software application.
Here at ScriptDorks we tested the migration tool from a phpbb forum and it was impressive how it kept all the posts and setup redirects to the new vanilla URLs. Vanilla has a much improved SEO friendly URL structure than phpbb.

phpBB

phpBB is a fast, efficient discussion board program built in PHP with a muti-database backend. Features include: posting, replying, private messages, polls, username/ip banning, strong encryption for storing passwords, user rankings, very advanced access control for private forums, full templating, simple yet robust translation system and much more.

Visit publisher site: phpBB