install Gnome with yum just as you would for KDE or xfce
from this list
Code:
su -
yum grouplist
--- install the Gnome group --
yum groupinstall " Gnome Desktop Environment"
check the list i may have miss spelled it
i am running OpenSUSE at the moment and not CentOS
and one more thing
READ THE MANUAL !!!! this IS IN IT !!!
red hat has made a BUNCH of docs for almost all if not ALL things
they are on the red hat web site
http://www.redhat.com/support/