I have a single site at http://www.domain1.com. It’s a PHP site being hosted on a Windows 2008/IIS 7.5 box. I need to set up http://www.domain2.com so that users are redirected to http://www.domain1.com/subfolder. To the user, they still see http://www.domain2.com in the address bar but are looking at the http://www.domain1.com/subfolder.
Any help on how to achieve this would be greatly appreciated!
You need to use IIS Application Request Routing and Url Rewrite modules. This walkthrough describes almost exactly what you are trying to achieve.