Install it with the command: yum install vnc-server.

The client program is 'vnc'. You can use the command yum install vnc to install the client if rpm -q vnc shows that it is not already installed.

Make sure to install a window manager in order to get a normal GUI desktop. You can use the command yum groupinstall "GNOME Desktop Environment" to install the Gnome Desktop and requirements.

When it's installed add a user:

useradd vnc

change the password of the user:

passwd vnc

login as vnc:

su vnc

Run the command vncpasswd. This will create a .vnc directory.

Edit /etc/sysconfig/vncservers:

VNCSERVERS="1:vnc"
VNCSERVERARGS[1]="-geometry 800x600"

Start the vncserver as root

service vncserver restart

now connect through a vnc client:

ip:1