Mapping is easy (as long as you have administrator access). Enter Internet Services Manager under IIS, bring up the properties for the web site, and go to the home directory tab. Click on "Configuration" next to the Default Application box. This will bring up a listing of the mappings. Use the add feature to map an application to an extention in IIS 4.0
In my case I mapped .cgi to
d:\perl\bin\perl.exe %s %s (don't forget the %s part).
Hope this helps.