Anyone know of any script that will authenticate users from an HTML login form against the Active Directory?

If you're using IIS, you should be able to just set the "Directory Security" to either Digest Authentication or Integrated Windows Authentication and disable anonymous access. That should do it. Of course, you need to make sure that you have enough cals to support the expected number of simultaneous visitors.

This would be a bit more than just directory security. It's going to be for an online control panel that would allow clients to manage a few things in regards to their web sites. The accounts are in the Active Directory so once they're authenticated they would be allowed to do so.

What language are you thinking of using? If you use ASP.NET (any language) you can use impersonation to have the scripts run as the user, that also gives you access to their user name (assuming you also use either Digest or Integrated Windows Authentication). Then you query their username to pull up the appropriate account information.

As for the "Directory Security", that's just the name for the tab/button in the IIS manager for the security settings. It just means that for the specified vroot (or site for that matter) the selected authentication is used (anonymous, simple, digest, or integrated windows). This also applies for all files under that vroot (or site).

I hope this helps.

I'm not quite sure to be honest, probably ASP as I've never done any ASP.NET applications (or have any ASP.NET servers). This control panel will be the one I posted an inquiry at http://www.webhostingtalk.com/showthread.php?s=&threadid=86863

Well all it takes to run ASP.NET pages is the .NET Framework and IIS, but it's up to you. It's better to use something you're comfortable with than to possibly open up a Pandora's box of new holes.

If you're using ASP, there is a request variable that gives you the user name when you use Integrated Windows Authentication. I don't remember exactly what it is right now since it's been a few months, but if I can find the code that uses it, I'll let you know. Then with that, you can load the appropriate information.

If you're familiar with it and know PHP, would you be interested in helping me with that project?