The below will show you how to add the Dag Wieers repository to Centos 5.3 I have also used this method for lower versions of Centos as well.
First you need to run this code from the console or via putty.
rpm –import http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt
In order to add this repository to your yum configuration for any version of RHEL, create the file /etc/yum.repos.d/dag.repo containing
[dag]
name=Dag RPM Repository for Red Hat Enterprise Linux
baseurl=http://dag.linux.iastate.edu/dag/redhat/el5/en/$basearch/dag
gpgcheck=1
enabled=1
You should now be able to use the Dag Wieers repository using YUM
