Installing Apache 2.0 and PHP 5 (and MySQL) on Windows XP
This web site is quite useful
http://www.expertsrt.com/tutorials/Matt/install-apache.html
I like this tip.
3.
Finally, add the following line, somewhere that seems sensible to you:
PHPIniDir "D:/Web/WebServer/PHP/"
(again, replace the path I used with the one you chose on your computer).
Note: If Apache does not seem to recognize your PHPIniDir directive, make sure you have the trailing slash (i.e. not PHPIniDir "D:/Web/WebServer/PHP"), as mentioned in the user comments in the PHP manual
Note Apache 2.2.2 and PHP 5 is not compatible at the moment I had to go back to Apache 2.0.50 version intor to get PHP 5 to work.