EPEL (Extra Packages for Enterprise Linux) is a volunteer-based community effort from the Fedora project to create a repository of high-quality add-on packages that complement the Fedora-based Red Hat Enterprise Linux (RHEL) and its compatible spinoffs, such as CentOS and Scientific Linux.
Adding EPEL repo is very easy:
wget http://ftp.heanet.ie/pub/fedora/epel/6/x86_64/epel-release-6-8.noarch.rpm rpm -Uvh epel-release-6-8.noarch.rpm
From unknown reason for me, CentOS 6.x goes without php-mcrypt package and it is impossible to install this rpm from base repos. Some apps will complain about this and one of the solutions is to install this rpm from EPEL repo… After you added EPEL repo, type:
yum install php-mcrypt