How to run php website on IIS 7 with ASP.NET website simultaneously
The process to do this is ( i suppose that IIS 7 is currently working and serving a ASP.NET website ) install php from microsoft web platfom installer ( you can get that here - http://www.microsoft.com/web/downloads/platform.aspx ) it will automatically install the dependencies .
Now php is installed and we will have to install CGI from control panel -> Program and Features - > Turn windows features ON or OFF
and check CGI features as shown in picture
Now simply add a new website in IIS with default app pool and your site is up and running with php installed .