Configuring IIS to Use PHP4
Use Internet Service Manager to create a Virtual Directory for your PHP files.
Select the Virtual Directory created.
Right-click to select the Property tab.
Click Virtual Directory tab.
Click Configuration, and then click App Mappings tab.
Click Add, and in the Executable box, type C:\php4\php.exe %s %s.
In the Extension box, type the file name extension to associate with PHP scripts, such as .php or .phtml. You can add only one extension at a time, so repeat this step as neccessary.
Restart IIS.