At long last, I've been able to update the HttpConfig GUI tool. I've fixed many bugs, streamlined the UI, added graphical security editing and gotten the thing to run on Vista.
Thanks to Keith and Dominick for the inspiration to enhance the security stuff. Now that I'm using .NET 2.0 for this app, I was able to get the EditSecurity API working purely in C#.
Enjoy!
Download: exe source