Although this book provides download and installation instructions for PHP 5.2, the newly-released (at the time of this writing) PHP 5.3 includes some new download options that aren’t covered in the book.
There are four different versions of PHP 5.3. for Windows: VC6 Non Thread Safe, VC6 Thread Safe, VC9 Non Thread Safe, and VC9 Thread Safe. Talk about confusing!
First of all, you definitely want a Thread Safe version of PHP. The Non Thread Safe versions are not suitable for use as a plugin for Apache.
Secondly, assuming you will install (or have already installed) a version of the Apache HTTP Server from httpd.apache.org (see page 13), you will need the VC6 version of PHP.
In short, to follow the instructions in this book, you need the VC6 Thread Safe
version of PHP 5.3 for Windows.