Sakrateri: Uninstall PHP from Add/Remove Programs in the Control Panel. Then reinstall it, and when it asks you what http server you have installed make sure to select Apache (IIS is selected by default I believe).
Once that's done, edit your httpd.conf file for the Apache server and add the following lines anyplace in the file (just change "c:/php/" in the following code to where you told it to install PHP):
Code:
# PHP stuff
ScriptAlias /php/ "c:/php/"
AddType application/x-httpd-php .php
Action application/x-httpd-php "/php/php.exe"
Hope this helps