Узнаем версию Centos
[root@server][~]
$ cat /etc/redhat-release
CentOS release 6.4 (Final)

Centos 5.x
$ wget http://dl.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
$ wget http://rpms.famillecollet.com/enterprise/remi-release-5.rpm
$ sudo rpm -Uvh remi-release-5*.rpm epel-release-5*.rpm

Centos 6.x
$ wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
$ wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
$ sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm