download - Pre-Built Packages と辿る。
http://nginx.org/en/linux_packages.html#stable
RHEL や CentOS のリンクがあるので、CentOS6のURLを確認する。
http://nginx.org/packages/centos/6/noarch/RPMS/nginx-release-centos-6-0.el6.ngx.noarch.rpm
# rpm -ivh http://nginx.org/packages/centos/6/noarch/RPMS/nginx-release-centos-6-0.el6.ngx.noarch.rpm
# less /etc/yum.repos.d/nginx.repo
# nginx.repo [nginx] name=nginx repo baseurl=http://nginx.org/packages/centos/6/$basearch/ gpgcheck=0 enabled=1
# yum -y install nginx
# nginx -v nginx version: nginx/1.6.2
# /etc/init.d/nginx start
# chkconfig nginx on