I had some trouble getting other peoples code to work for AD support, so I wrote my own which authenticates against LDAP and will also use SSL and cert if required. It will also verify that an autheticated user has specific group membership before authorizing.
This will also debug to a file, which is really helpful when trying to figure out problems.
One thing that really got me when getting python-ldap to work was that you must have "ldap.set_option(ldap.OPT_REFERRALS,0)" set or any ldap search will not work.
Also, this will add group permissions to a user.