Dedoimedo posted a guide about installing the Nvidia proprietary driver in CentOS 6.0

Something handy for everyone, from your grandpa to your clueless friends, if you have any. Well, not really, but still a jolly good geek read. A tutorial explaining how to install the Nvidia properietary driver in CentOS 6, including manual download, installation of build tools (kernel sources, headers, gcc, make), blacklisting Nouveau driver, switching runlevels, installation from command line, testing, and more.

  How to install the Nvidia proprietary driver in CentOS