Extra Packages for Enterprise Linux (EPEL) is a repository of packages maintained by a group of Fedora project volunteers for use with Red Hat Enterprise Linux (RHEL) and it's derivatives such as CentOS and Scientific Linux.

One of the stated goals of the project is "EPEL packages are usually based on their Fedora counterparts and will never conflict with or replace packages in the base Enterprise Linux distributions".

Like CentOS, distros based on RHEL use the same numbering scheme for their releases so, for example, CentOS 6.3 is the same as RHEL 6.3.

To set up the EPEL repository login in to your server as root via SSH and run the following commands:

Red Hat/CentOS 6.x

wget http://fedora.mirror.nexicom.net/epel/6/i386/epel-release-6-8.noarch.rpm
rpm -i epel-release-6-8.noarch.rpm

Red Hat/CentOS 5.x

wget http://fedora.mirror.nexicom.net/epel/5/i386/epel-release-5-4.noarch.rpm
rpm -i epel-release-5-4.noarch.rpm

That's it. Your server is now set up to install packages from EPEL.