This tool (from Mark Russinovich and Bryce Cogswell) is basically ADSI Edit on steroids. It allows you to connect to your AD environment directly thus providing you a "raw" view of your directory and in turn the ability to change the directory directly(which might cause a lot of pain since...
ADModify is a tool that will enable an AD/Exchange admin to make bulk changes in user properties. One of the special treats of this tool is the fact that it provides a simple GUI for configuring the accepted MAPI level for clients. You can download the tool at: http://www.gotdotnet.com/workspaces/workspace...