That might just possibly depend upon what distribution you're using, which you don't seem to have specified.
If you're using gentoo, for instance, you'd want to emerge an appropriate version of the nvidia-drivers, as well as making sure that your kernel is properly set up, that your xorg.conf is suitably modified, and that you eselect the nvidia-drivers package. A search for 'gentoo nvidia' turns up a proper guide as the very first hit on Google.
If you're using another distribution, the answer will be entirely different. No matter what it is, there is probably a distribution-specific HOWTO on it. For many if not most distributions, the process will probably be simpler than that for Gentoo.