Работа с объектами "пользователь" или "компьютер".
http://daniellange.wordpress.com/2010/01/28/get-any-ad-user-or-computer-object-property-in-powershell-quickly/
http://daniellange.wordpress.com/2010/01/28/get-any-ad-user-or-computer-object-property-in-powershell-quickly/