There is a great big world out there just waiting for you to join
Anyone that codes with PHP (professional or amateur, full time, part-time, hobbyist, expert and beginner ), uses or writes PHP software (Joomla, Drupel, phpMyAdmin, etc - actually can be considered sub-communities.), answers questions on the mailing lists or forums, attends user group meetings, teaches others to use PHP (office, univ, etc).