To control your RaspberryPI through VNC using another computer do this:
Inside the RaspberryPi:
Install x11vnc
:
$ sudo apt-get install x11vnc
Then, execute x11vnc
as follow to assign a password that must be used when connecting to your VNC server:
$ x11vnc -storepasswd
Enter VNC password:
Verify password:
Write password to /home/pi/.vnc/passwd? [y]/n
Password written to: /home/pi/.vnc/passwd
Inside your other computer:
$ sudo apt-get install x11vnc
$ x11vnc_ssh pi@192.168.1.57:0
Here 192.168.1.57
should be the IP of your RaspberryPi. This will ask for a password, which is the same you assigned inside your RaspberryPi to the VNC server.
This is the expected result:

Note: In my case the x11vnc_ssh
is too verbose, so much that I couldn't see the password prompt from the server. So I chose to "disable" the stderr like this:
x11vnc_ssh pi@192.168.1.57:0 2>/dev/null
Hope it helps.