From Steve Bostedor:

VNCScan was the first scanning and management application for VNC.  Since
version 1 was released in 1997, TGCS has been committed to innovating new
features that save you time and frustration.  This is a $30 shareware
application with full commercial support.  The free Microsoft DotNet framework
and MDAC 2.7 are required.

With VNCScan, you can:

* Scan up to a class A address space
* Check the status of a single computer without a rescan
* Scan multiple ranges per group of computers
* group scan ranges into logical structures
* Remotely deploy VNC to NT/2L/XP desktops with FastPush script
* Configure the FastPush script with a GUI
* Start and stop the remote VNC service
* Reboot the remote computer
* Ping the remote computer
* Export computers to HTML
* Check the version of VNC on enabled clients
* Find who is logged into enabled computers
* Connect to Windows file shares on remote computers
* Move computers (drag and drop) between groups
* Manually add computers to groups
* Keep track of status of computers with visual effects

You can get a copy here: http://www.vncscan.com