I've been working on this script for the last week for my school's admission office. I'm no vbscript expert, but I know enough to get things to work. The script is able to achieve minimal downtime by using Microsoft's volume shadow copy service (the script will work only for Windows XP and Windows Server 2003; it may work for Vista as well, if you can find vshadow.exe for it), which you'll have to download (search vss sdk at http://www.microsoft.com/). This script is and adaptation of a script previously posted in this forum by saxa which can be found here: http://communities.vmware.com/thread/54782. Make sure to read all the comments in the beginning and follow any instructions. I haven't tested very thoroughly, so if you find problems, tell me and I can try to fix them. Enjoy! (The script is attached) Do not just run it; save it then right click edit it to read the comments in notepad.
-Zack Nicolaou