It cant be too simple, this topic write for newbie only.
modify one char in /etc/inittab.

use this command:
vi /etc/inittab
find this line
id:5:initdefault:
change it to
id:3:initdefault:

save and exit then you are good to go.
if you need enter xwindows from command line, type
startx

below is an example of /etc/inittab
[root@fedora8 ~]# cat /etc/inittab
#
# inittab This file describes how the INIT process should set up
# the system in a certain run-level.
#
# Author: Miquel van Smoorenburg,