The following article will article CentOS 5.x-based or Centos 6.x-based system using Fedora Epel repos, and the third partyremi package repos. These package repositories are not officially supported by CentOS, but they provide much more current versions of popular applications like PHP or MYSQL.
Install the extra repositories
The first step requires downloading some RPM files that contain the additional YUM repository definitions.
wget http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm wget http://rpms.famillecollet.com/enterprise/remi-release-5.rpm sudo rpm -Uvh remi-release-5*.rpm epel-release-5*.rpm
wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm
Once installed you should see some additional repo definitions under the /etc/yum.repos.d directory.
$ ls -1 /etc/yum.repos.d/epel* /etc/yum.repos.d/remi.repo /etc/yum.repos.d/epel.repo /etc/yum.repos.d/epel-testing.repo /etc/yum.repos.d/remi.repo
Enable the remi repository at Time of install
The remi repository provides a variety of up-to-date packages that are useful or are a requirement for many popular web-based services. That means it generally is not a bad idea to enable the remi repositories by default.
You will now have a larger array of yum repositories to install from.