WMI Explorer is a very handy tool for understanding and exploring WMI classes & Name spaces in Windows environment. The good thing about this tool is its ability to display instances, properties and methods of a given class. You can explore the WMI classes and namespaces available in other computers as well using this tool.
You can download this tool from here
SAPIEN also has similar tool but its licensed. You can still try the trial version of it. You can download it from http://www.sapien.com/software/wmiexplorer