Where does Microsoft IIS stores its settings?
IIS 7 and above introduced an XML based configuration system found in the following directory:
%WinDir%\System32\Inetsrv\Config
By physical path I'm assuming you mean a website's, which is found in:
%WinDir%\System32\Inetsrv\Config\applicationHost.config
For further information visit:
http://www.iis.net/ConfigReference