From: ken gebser@mousecar.com
At work I've been asked to set up vnc for a remote user (a vendor sysadmin to install 3d party software we've purchased). Of course I'm a bit skittish about allowing root access to this. Is there a way to configure vnc so that root cannot log in through it...? Or do I have to use some other utility to deny root access (e.g., securetty).
Maybe check the wiki: http://wiki.centos.org/HowTos/VNC-Server I would guess you just don't give root's vnc password?
JD