Do the following
1. Install X11VNC server with sudo aptitude install x11vnc vnc-java. You need root access to use aptitude to install x11vnc package
2. After installing, type x11vnc -storepasswd to set up password for client access.
3. Make sure you disable or configure your firewall to allow 5800 and 5900 for remote access
4. Then, at command prompt, type x11vnc -forever -usepw -httpdir /usr/share/vnc-java/ -httpport 5800 to run the server.
5. Now, use your vnc viewer or use your browser http://ip:5800 to access your remote machine.