Well, for the case you describe, VNC is not needed at all. Using ssh sessions would be sufficient for your purposes - the Linux ssh client, or for instance
PuTTY for Windows computers.
BTW I am writing up a Wiki article based on this LQ thread:
http://www.slackware.com/~alien/doku...lackware:proxy
It is not nearly finished yet (I don't have access to my own server's configuration files) but it does already have quite some information. If you have hints on what is missing or could be phrased clearer, please let me know in this thread.
Eric