Howtoforge posted a guide about installing Nginx with PHP5 on CentOS 6.3

Nginx (pronounced "engine x") is a free, open-source, high-performance HTTP server. Nginx is known for its stability, rich feature set, simple configuration, and low resource consumption. This tutorial shows how you can install Nginx on a CentOS 6.3 server with PHP5 support (through PHP-FPM) and MySQL support.

  Installing Nginx With PHP5 (And PHP-FPM) And MySQL Support On CentOS 6.3