I run into this all the time and keep needing to Google for it, so I may as well document it here. 

If you need to test a site with https during development, you need to use the IIS 6 Resource Kit to generate a self signed certificate.  No sense in repeating the steps here when this excellent post shows all the steps.

Notes:  The IIS site id can be found using the following commmand:  execute iisweb.vbs /query "<NAME OF THE WEBSITE>"