You'll also want to go edit /etc/inittab and where it says:

id:5:initdefault:

change it to

id:3:initdefault:

This will make RedHat boot into terminal mode without starting X. That way, if you have any display problems in the future, you'll still be able to easily log in and fix whatever went wrong.

If you want to start up X when in this mode (init 3), just log in as a user and type:

startx