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.

Invision Power Board (IPB) is a professional forum system that has been built from the ground up with speed and security in mind, taking advantage of object oriented code, highly-optimized SQL queries, and the fast PHP engine. A comprehensive administration control panel is included to help you keep your board running smoothly. Moderators will also enjoy the full range of options available to them via built-in tools and moderators control panel. Members will appreciate the ability to subscribe to topics, send private messages, and perform a host of other options through the user control panel.

Phorum is a little different from the other web based message boards out there. It was designed to meet different needs of different web sites while not sacrificing performance or features.

W-Agora (Web-Agora) is a professional database-driven communications system which allows you and your visitors to store and display messages, files, and other infos on your web site. Features: Threaded or flat discussions, attachments, Users managements, private forums, Multiple sites & forums, Multi-languages support, Fully customizable using templates, Full web-based admin panel, statistics, Multi-Database support, Search engine, WYSIWYG editor, and more... Commercial support is available.

Ultimate PHP Board is a free discussion forum that can be used as a free alternative to UBB or vBulletin. UPB uses text files to store data, no database needed to run. Features: umlimited categories/forums/topics; online admin (members, categories, forums, config); profiles; forum stats; css; skins support; smilies; cookie-based login; threaded discussion; encrypted passwords; fully functional search - setup within 3 min; and more. 1.9.6 update - many fixes and private messaging system included!

XMB is a free message board powered by PHP and MySQL. The extensive control panel allows extreme control over all aspects of the message board system including these features...unlimited posts, forums, members, administration panel, members panel, multiple themes, word censors, user ranks, custom titles, member list, whos online, BBCode, HTML, Instant Messenger, flood control, thread administration options, bump, top, delete, open, close, move and more. Avatars, sub-forums, post pruning, smilies, polls, forum/post subscriptions, favourites, custom templates, FAQ, attachments, COPPA support and more. XMB 1.9 Nexus features new security to prevent from mass registration, IP monitoring and fake registration processes.

Zorum is an easy to install Web-based forum, message board, or bulletin board. It requires a MySQL database,and the PHP4 script module. Features include: web based easy install, embedded administration, personalization, moderators, password reminder, post blocking rules, bb code, mark unread messages, subscriptions, attachments, ratings, polls, smilies, word censoring, search, statistics and more.

miniBB (minimalist bulletin board) is a free, complete web forum software script, PHP bulletin board. Professional by speed, ascetic by size, powerful by rule, it includes the most common forum functions for various size communities. Features: CSS- and HTML-template based (W3C compatible), various databases supported (mySQL is default), plugins, multilingual, mod_rewrite, SEO. Can be integrated into your web site or another PHP project with the best fit, both by layout and using advanced members database authorization module.

WoltLab Burning Board is a bulletin board software based on PHP4 and MySQL. Bunrning Board has many features that sets it apart from similar forum software: HTML Templates, User profiles (editable by user), User groups - give select moderators/users admin powers, Private forums, Word censor, Ban users, Support for smilies, BB Code or HTML in messages, and much more. Burning Board is available in English & German.

OpenBB is a fast, lightweight, powerful bulletin board written in PHP/MySQL. Main features include: full customization via styles/templates, instant messaging, private messaging, categories, member ranks, poll based threads, moderation, BB codes, thread notifications, Avatars, member lists, private forums and more.