"The configuration system that PHP uses for installation is one
of those nice, simple things in life that makes it rosy. At first
it might seem a little confusing, but it's really very easy. So
let's dive right in."
"To download PHP, visit the php.net download page and click the
link under the heading "Complete Source Code."
"The first thing to do after downloading and unpacking your
source archive is to kick the tires a little bit."