For anyone doing regular checks of Microsoft AD this tool is a must have:

With the Active Directory Topology Diagrammer tool, you can read your Active Directory structure through Microsoft ActiveX® Data Objects (ADO). The Active Directory Topology Diagrammer tool automates Microft Office Visio to draw a diagram of the Active Directory Domain topology, your Active Directory Site topology, your OU structure or your current Exchange 200X Server Organization. With the Active Directory Topology Diagrammer tool, you can also draw partial Information from your Active Directory, like only one Domain or one site. The objects are linked together, and arranged in a reasonable layout that you can later interactively work withthe objects in Microsoft Office Visio.