Basically I followed this step-by-step from Microsoft, but for my own sake I’m writing my own so it’s easier to find.

Setup IIS from Windows Control Panel

• Open Control Panel >> Programs >> Turn Windows features on or off

• Select Internet Information Services >> Expand and check CGI under World Wide Web Services — Application Development Features

• Test by opening http://localhost/ on your browser

Download and Install PHP

• Create a C:\PHP folder on your local drive

• Download latest PHP non-thread-safe zip package from Windows PHP Download Page

• Download WinCache from SourceForge

• Extract PHP zip files to C:\PHP

• Extract WinCache zip files to C:\PHP\ext

• Open Control Panel >> System and Security >> System >> Advanced System Settings

• On System Properties >> Go to Advanced tab and add a C:\PHP System Variable under Environment Variables

• Open IIS Manager >> Select your machine under connections >> Open Handler Mappings

• Add Module Mapping with the following details:

• Request path: *.php
• Module: FastCgiModule
• Executable: C:\PHP\php-cgi.exe (location of php-cgi.exe within your PHP folder)

• Add Default Document by going to Default Document >> Add >> add default.php and index.php

• Create a PHP Info page to test

• Create a phpinfo.php file on Notepad++ (run as Admin) with the following code: 
  <?php phpinfo(); ?>  
  … and save inside C:\inetpub\wwwroot\

• Open http://localhost/phpinfo.php on your browser and you should see this page

End. 🙂

Hope this helps.