Since its creation in 2000, PhPBB has become the most widely used Open Source forum solution. Like its predecessors, PhPBB 3.0 "Olympus" has an easy to use administration panel and a user friendly installation process, which allows you to have a forum set up in minutes. With a large and highly customisable set of key features coupled with a standards compliant interface, PhPBB will grow with, and complement your website. With millions of installations worldwide, it is no wonder PhPBB is one of the most popular ways to create and support a community.
Documentation: Good documentation covering all aspects and customizing of PHPBB forum.
Community: Community is rather large and active. You can find lot of themes created by users,
Simple Machines Forum - SMF in short - is a free, professional grade software package that allows you to set up your own online community within minutes. Its powerful custom made template engine puts you in full control of the lay-out of your message board and with our unique SSI - or Server Side Includes - function you can let your forum and your website interact with each other.
Community: Community includes several active forums and chat.
PunBB is a fast and lightweight PHP-powered discussion board. Its primary goals are to be faster, smaller and less graphically intensive as compared to other discussion boards. PunBB has fewer features than many other discussion boards, but is generally faster and outputs smaller, semantically correct XHTML-compliant pages
Documentation: There is large wiki with documentation.
Community: Laarge community includes several forums, wiki and international support.
aterr is an open source threaded forum system; allowing registered visitors to express their opinions, discuss topics, and debate with other visitors. A threaded forum system differs from regular, flat forum systems in that once posted, a thread can fork, allowing visitors to reply directly to other posts. aterr also provides a customisable permissions system, the ability to nest forums, and moderation tools.
Documentation: Weak. Small instruction how to install forum.
Community: Community includes support forum and IRC channel
The Unclassified NewsBoard (short UNB) is an open-source, PHP-based internet bulletin board system, mostly like those you may already know. But the difference is in a lot of details that make your life with this board, both as administrator and user, much easier.
Documentation: Medium. Documentation covers only basic operations with forum.
bbPress is plain and simple forum software, plain and simple. It's easy to use, easy to administrate, fast and clean. But don't let its simplicity deceive you; underneath the gleam, it's got some powerful features and is highly customizable.
Documentation: Documentation is clear and compact.
Community: You can find developers s blog and active forum on the bbPress site. Also there is a mailing list and IRC channel.
Ikonboard is a comprehensive web bulletin board system. It transcends the limits imposed by other bulletin board software, allowing you to create a truly unique community on your website. From it's extensive template and skins features to it's complete multi-lingual support, your members will keep coming back for more.