Is it possible to use the standard HTTP Authentication (the one with the little pop-up box, like if you were logging into a router or something).
Only thing I've found googling is using PHP+mysql. While I could do that, it seems like overkill for this application.
Usually with apache on a unix service, I would add a '.htaccess' file and specify that it required a certain user, then put the encrypted password in a file out of web site directory.
I was looking at the IIS management and it seems the only thing you can do there is link directory security to a windows user / password on that machine.