suPHP is a tool for executing PHP scripts with the permissions of their
owners. It consists of an Apache module (mod_suphp) and a setuid root
binary (suphp) that is called by the Apache module to change the uid of
the process executing the PHP interpreter.

This version was compiled to look for its config-file in /etc/httpd
rather then just /etc as 'httpd' looks there aswell.

Some of the 'standard' /etc/httpd/httpd.conf directives include:

  LoadModule suphp_module  /usr/lib/httpd/modules/mod_suphp.so
  suPHP_Engine on
  AddHandler x-httpd-php .php
  suPHP_AddHandler x-httpd-php  
  suPHP_UserGroup someuser users

To use different php versions 'per vhost' see:
http://www.howtoforge.com/apache2_suphp_php4_php5

mod_php can be reduced (greatly) by rebuilding PHP for FastCGI and 
using mod_fcgid; however, that requires additional configuration.
See http://fastcgi.coremail.cn/configuration.htm for details.
