I have a Multi-Site Installation that was originally set-up

I have a Multi-Site Installation that was originally set-up as a sub-domain site. I want to change it to subdirectory. I have found a few different types of instructions on how to do it, including the .htaccess file. The problem is that I am running IIS 7.5 and need the web.config equivalent. Is there any way you can help or point me in the right direction?