Here's how to install the nVidia drivers if the RPM doesn't work (or if you don't want to use the RPM):
- Get the lastest linux drivers.
 - Now print this out, or write it down, because we're going to close X, the graphical part of Linux.
 - Open a Terminal.
 - Become root: 
su -
 - Shut down X: 
telinit 3
 - Now, you will have a "Login:" prompt. Log in as root and go to the directory where you downloaded the nVidia drivers.
 - Type: 
sh NVIDIA-Linux-x86-1.0-6106-pkg*.run
 - Type: 
cp -a /dev/nvidia* /etc/udev/devices/
 - Type: 
chown root: /etc/udev/devices/nvidia*
 - Follow nVidia's instructions to set up the driver. (Read the "EDITING YOUR X CONFIG FILE" section.)
 - Now, we need to remove some conflicting files:
			
rpm -e --nodeps xorg-x11-Mesa-libGL
				NOTE: If you update any "xorg-x11" package with up2date or yum, 
				you will have to do the above command again.
			
				NOTE: Some users report that removing this package is not necessary for them.
			 - Type: 
modprobe nvidia
 - You can now restart X by typing: 
			
telinit 5
. 
		
		NOTE: You must re-do these steps every time you install a new kernel with yum or up2date.
	
(Thanks to Dexter Ang for helping me simplify this answer! Thanks to Vahe Sarkissian for a good correction. Thanks to D. Michael Basinger for letting me know that you have to do modprobe nvidia.)