[TECK]

Very good, we are getting there, if you get a 403 we are in business.
Now, install PHP.

Go to PHP site and download this package:
PHP 5.2.1 zip package [9,545Kb] - 08 Feb 2007
http://www.php.net/downloads.php

Extract it's contents to folder C:\inetpub\php
Drop inside the above mentioned folder the file I attached into this post and rename it to php.ini

Now, just to make sure, double check this:
Go to IIS console and right-click on Web Sites > Properties
Click on tab Documents, you should already have there index.php
Don't close it we need it on the next step.

Next, we need to add the .php extension into IIS so it gets recognized.
Click on Home Directory tab, beside Documents (window still open)
Click on Configuration button
On Mappings tab, click on Add button
Executable: Browse to executable php-cgi.exe, located in C:\inetpub\php
Extension: .php
Limit to: GET,HEAD,POST (no spaces)
Click OK 3 times.

PHP is installed, reboot your PC.