Yum is a great update manager for RedHat/CentOS Linux. Unfortunately, default repos are typically way behind the stable releases of the packages contained in them. If you need to install PHP, MySQL, Python or other major package, you will find that the versions in default repos are old to the extent of being useless. This used to force Yum users to resort to third-party repositories and many open-source volunteers have hosted latest versions of packages as yum repositories, helping and assisting the community.

While most efforts were noble and honest contributions, it's always tricky to install packages from unknown sources. The dark fear of "what if" will nag you and your security team (if you have one) will point you to the door. Now there's a good solution, however. One of the most trusted names in the industry, Rackspace hosting now has a Yum repo for popular RedHat packages.

The wiki documentation for how to install and use it can be found at: http://wiki.iuscommunity.org/Doc/ClientUsageGuide

Please note that currently the links on the wiki seem to be outdated/broken, so to install the repo on a 64-bit CentOS 5.x, you actually need to run:

sudo rpm -Uvh http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/epel-release-1-1.ius.el5.noarch.rpm 
sudo rpm -Uvh http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/ius-release-1.0-6.ius.el5.noarch.rpm 

On 32-bit CentOS 5.x the commands would be:

sudo rpm http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/i386/epel-release-1-1.ius.el5.noarch.rpm 
sudo rpm http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/i386/ius-release-1.0-6.ius.el5.noarch.rpm