Users in Active directory

Is it possible to use the active directory as a source for the user data? I already have the code to talk to the active directory.

Might be, although not trivial. Not sure if you want to just import Active Directory users or allow Sphinx to detect a logged user and automatically do the login.

You can somehow reimplement TUserManager for some low-level tasks, but I'm not sure if it's possible to do a full login system right now.