This tool installs onto the server, and uses the Security ACL permissions to determine who is allowed to see the folder listed in their Windows Explorer or command line directory listing.
When installing the tool, one has the choice to enable enumeration on all shares, or choose to enable it on individual shares later on. I always choose the manual option.
Once installed, you will find a new tab in your folder properties window.
Once clicked on, you are presented with the option to enable enumeration on the folder.
Once enabled, only those users that have permission to access the folder will see it in their Explorer. This goes for folders listed in the Network Neigbourhood/My Network Places listings on the server.
The documentation can be found here on Microsoft's site.
The actual download can be found here. Note the different downloads for different processor architectures.
Microsoft Small Business Specialists