PHP Forum: 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.
phpBB is based on PHP, the fastest growing server-side scripting language on the web, which results in one of the fastest, feature-rich bulletin board systems available anywhere.
In addition, phpBB is open-source software so it has no fees, no subscriptions, and no restrictions on modifications. Couple this with a thriving and friendly phpBB community and you have a killer solution for creating communities on your site!
Remember, phpBB Support is completely free of charge, for now and forever. Developers, team members and fellow users are always available to answer your questions, and help you troubleshoot any problems you may have. It´s quick, easy, and doesn´t cost a penny!