:: what is epel repository
The EPEL (Extra Packages for Enterprise Linux) repository is a community-based effort from the Fedora Project to bring Fedora packages to RHEL and CentOS.

:: how to install epel repository on linux centos
64bit

# rpm -Uvh //download.fedora.redhat.com/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm

32bit

# rpm -Uvh //download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm

:: links
+ google
+ ridingthecloud