This section contains notes and hints specific to installing
  PHP on Mac OS X. There are two slightly different versions of
  Mac OS X, Client and Server, our manual deals with installing
  PHP on both systems. Note that PHP is not available for MacOS
  9 and earlier versions. 
 
   There are a few pre-packaged and pre-compiled versions of PHP for
   Mac OS X. This can help in setting up a standard
   configuration, but if you need to have a different set of features
   (such as a secure server, or a different database driver), you may
   need to build PHP and/or your web server yourself. If you are unfamiliar
   with building and compiling your own software, it's worth
   checking whether somebody has already built a packaged
   version of PHP with the features you need.