VNC is a software to graphically remote computers, available for every OS.

Since I’m leading my familly/friends to the Open-source/Ubuntu way, They need support especially graphical (better that “heuuu the window on the top left…..”) And I cannot ask them: ” open a terminal, type sudo apt-get install x11vnc then enter” Coz I saw people typing “e-n-t-e-r”
For Windows-Ubuntu or Windows-Windows Ultra VNC Sigle-Click contain all the features.

Here is a small How-to made from differents part picked-up around Internet to make it working as the windows one (one click)
I assume you know more than the dude on the front of you, that mean you know that if you receive a connexion the the 5500 port, you will not forget to forward it on your router.
Your Computer:

sudo apt-get install vncviewer

vncviewer -listen

Make a file with in:

#!/bin/sh
gksudo "apt-get install -q -y x11vnc"
x11vnc -connect_or_exit xx.xx.xx.xx -rfbport 0 -nopw

Where xx.xx.xx.xx is your IP address, the public one.
Save it as “Helpdesk-Linux” , set it executable and send it to your friend by email.

Your Friend’s Computer:

Start the script file and thats all.

You can alternatively install x11vnc and start the connexion with:

sudo apt-get install x11vnc

x11vnc -connect your.external.ip.address:5500

But the version is few releases late.

Sources:

Tuto from ubuntuforum:

http://ubuntuforums.org/showthread.php?t=299489

x11vnc webpage’s project:

http://www.karlrunge.com/x11vnc/

How to for .deb from sources:

http://www.quietearth.us/articles/2006/08/16/Building-deb-package-from-source