Try editing you local hosts file. The default location is %SystemRoot%\system32\drivers\etc\hosts in most Windows systems.
Then you simply add the line
127.0.0.1 simdomain.com
That should do it.
EDIT: Ah, and as Chakrit said: Open IIS admin and add a "simdomain.com" website. So it knows the domain.
This depends a bit on IIS version, but if I remember correctrly for IIS7 do as follows:
- Run 'inetmgr', or access the IIS setings via the Control Panel.
- In the menu on the left open 'Sites', and right-click on the site you want to access. Choose 'Edit bindings..'
- Click add. Type: Http, IP Address: All Unassigned, Port: 80, Host name: simdomain.com then click OK.
Might as well make my answer correct, even if the post is a tad redundant. ;)