All with VNC

How to enable VNC on linux machine (RedHat) with Display 0

Edit the file /usr/X11/xorg.conf

Add the lines
In the "Modules" section add
SubSection "vnc"
Option "Desktop" "My workstation"
EndSubSection

In the "Screen" Section add
Option "SecurityTypes" "None"

Note you can enable various security types. Easiest is None! :)