I've taken DAL out of ATL to Europe a couple times. The above post is correct. You will need to go to the International customer service counter and get "passport listed" Also, this has to be done 75 OR 90 minutes prior to go time. I can't remember which. If you don't do this, YOU ARE NOT GOING TO GET ON THE FLIGHT, PERIOD.
I don't believe that DAL has a restriction on the amount of int'l JS'ers. I heard that UAL does. And not even their own guys can give you a straight answer on that.