Looking for Network Mapping and Server Configuration Program

Hi All,
Our organization needs a program that maps our entire network and can tell us how our Servers(DNS, ISA(proxy), Exchange, etc.) are configured.

The Network-Administrators who setup our network have left our company for other jobs, but they did not leave any kind of documentation on how our servers were configured. We will soon be upgrading our servers for MS2008, but my boss has asked if there is a program that can get information on how our servers were configured before we upgrade from 2003 Server to 2008 Server.

If anyone knows of an application that can mapp our network and get the server’s configuration settings, that would be great. Thanks in advance.