Authentication Plug-in for PHPBB using External MySQL Table Source http://nzeyimana.nefa.se/2009/04/authentication-plug-in-for-phpbb-using-external-mysql-table-source/

###USAGE To use this plugin, copy it to the directory /includes/auth/ (the file should be /includes/auth/auth_dbext.php ) in your PHPBB3 install location.