My daily duties as a sys admin today included installation and configuration of SuPHP. SuPHP is an apache dynamic module for executing PHP scripts with the permissions of their owners. More here
It consists basicly of twoparts Apache module (mod_suphp) and a setuid root binary (suphp). The suphp module is invoked by the mod_suphp module and instructsApache to change the user id (uid) of the process executing the PHP script.