By default CentOS Yum has a pretty poor selection of packages compared to something like Debian. So it can be a good idea to add RPMForge to get access to more up to date packages.
cat /etc/redhat-release uname -a
Now choose the appropriate repository for the CentOs version and architecture:
Install the repo:
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt rpm -K rpmforge-release-0.5.2-2.el6.rf.*.rpm rpm -i rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
You should now have access to a heap more packages via Yum.