“The CentOS-5.6 Continuous Release CR repository is now available on mirror.centos.org. This repository contains rpms to be included in the next CentOS-5.x release. Because these include security and bugfix updates, we strongly recommend everyone using CentOS-5 install and update their system using this repository.”

via [CentOS-announce] CentOS-5.6 Continuous Release i386 and x86_64.

Particularly useful if you are running Centos and want the latest Apache httpd rpm, fixing the range DoS.