EPEL
From Consultancy.EdVoncken.NET
EPEL (Enhanced Packages for Enterprise Linux) is an excellent repository for all your CentOS / RHEL machines. It contains a lot of the packages that are missing from the main distribution.
Enabling the EPEL repository
Download the appropriate epel-release RPM for your operating system (version 4/5, architecture i386/x86_64) and install it:
wget http://ftp.surfnet.nl/pub/os/Linux/distr/fedora-epel/5/x86_64/epel-release-5-3.noarch.rpm yum install /path/to/epel-release-5-3.noarch.rpm
Note: I found that yum sometimes fails to download the package - this is why I download it using wget.
Importing the EPEL package signing key
The first time you attempt to install an EPEL package, Yum will attempt to import the EPEL package signing key:
Importing GPG key 0x217521F6 "Fedora EPEL <epel@fedoraproject.org>" from /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL Is this ok [y/N]: y