[CentOS-announce] CentOS-6.0 Continuous Release i386 and x86_64: http://lists.centos.org/pipermail/centos-announce/2011-September/018078.html
The centos-release-cr-6.x rpms are available in the Extras repository. You can either run: 'yum install centos-release-cr', and follow yum's prompt or download the rpms directly, install them using rpm and then use yum to run the system updates.