Programmatically how to get version of Exchange server   

Hi All,
    I need a way to determine the version of Exchange server
( Exchange 2000/ Exchange 2003 and Exchange 2007 ) using win32 call.
Any idea how do i get this? Any sample code available to refer?

Regards,
Shivaraj

date: Mon, 08 Oct 2007 01:45:18 -0700   author:   shivaraj