The latest version of Puppet can be installed on CentOS by adding the Puppetlabs repository and then installing the official Puppet package:
rpm -Uvh http://yum.puppetlabs.com/el/6/products/i386/puppetlabs-release-6-7.noarch.rpm yum install puppet
This will install the latest official version of Puppet. Check the version by issuing this command:
puppet --version
At the time of writing, the latest version was 3.2.4.
Installing latest version of Puppet on CentOS