phpBB is a most popular and wide-used open source PHP forum script, you can used it to stay in touch with a group of people or can power your entire website. With an extensive database of user-created modifications and styles database containing hundreds of style and image packages to customise your board, you can create a very unique forum in minutes.
Another free and open source PHP forum scripts with a twist from the creators of WordPress. bbPress is plain and simple forum software, plain and simple. It’s easy to use, easy to administrate, fast and clean.
SMF is a free, professional grade software package written in the popular language PHP and uses a MySQL database. SMF allows you to set up your own online community within minutes and provides you with all the features you need from a bulletin board while having an absolute minimal impact on the resources of the server.
MyBB is a forum package full of useful and to-the-point features for both you and your visitors, helping you to make running your bulletin board as easy as possible. MyBB has a large amount of plugins that are ready for you to use.
SEO-Board is a forum software written in PHP and uses MySQL as a back-end. SEO-Board is fast, free, and search engine friendly and forever 100% free for both personal and commercial use.
PunBB is a fast and lightweight PHP-powered discussion board and is released under the GNU General Public License.
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.
FluxBB is a lighter, faster forum applications released under the GNU General Public Licence. It is easy to use and has a proven track record of stability and security making it an ideal choice of forum for your website. FluxBB is a fork of PunBB, the current stable release is FluxBB v1.4.2.
Vanilla Forums are open-source, standards-compliant, customizable discussion forums.
Phorum is a PHP and MySQL forum software based on Open Source. With a flexible hook and module system, Phorum allows a you to create modules for using external authentication, altering message data before its stored, adding custom information about users or messages and it can give the web designers the power to rearrange the data in any shape, form or fashion they could want.
IceBB is a powerful, fast, free, and open-source forum solution powered by the free PHP and MySQL. IceBB scales well, no matter how many users or posts, due to its clean and efficient code. It can also be fully customized to your needs with full skin and language support.
UseBB is an ideal solution for small to medium-sized websites which require an easy to use forum package without the bloat, that produces standards compliant output, is secure and easily configurable. UseBB is one of the easiest and most usable forum packages without an excess of features, limiting the basic feature set to only the essential. UseBB is pure forum software.
XMB provides key features for you to get your message board up and running and it has easy to use Member Management system, theming interface and anti-spam image verification system.