x11-vnc-monitor is a gui frontend for x11vnc server. You will need to install the x11vnc package first to use this.
x11-vnc-monitor will tell you at a glance if the x11vnc server is running or not. It also allows you to configure the x11vnc server by setting a few options. You can close the server monitor and open it any time without affecting the x11vnc server program. If anything, this may help you to setup the x11vnc server on your computer.
This will work on 64bit Linux systems (tested on Xubuntu so far). Please feel free to let me know if it's not working on your distribution.
If you have any suggestions, please get in touch via email. Many thanks.