This article provides an example for getting started with the Active Directory service monitor.

Try the following settings when initially configuring your Active Directory service monitor:

Host: <AD hostname> 
Port: 389 
Password: <password from user listed in bind string>
Base: CN=Users,DC=domain,DC=com 
Bind: CN=Craig Finn,CN=Users,DC=domain,DC=com 
Attribute: sAMAccountName 

Replace CN=Craig Finn with the user account you wish to query.  If you are not completely familiar with the hierarchy of your AD setup, there are free AD browser tools available such as AD Explorer, which is available at the Microsoft Technet website.