From LXF Wiki
CentOS is an a rebuild of the Red Hat Enterprise Linux source code, striving to maintain binary compatibility. It is useful for those who want to develop for or test on Red Hat's high-end and long-support Linux offerings, but don't want to pay the licence fees.
Current Version: 5.0 (CentOS-announce Thu Apr 12 22:36:44 UTC 2007)
Package: RPM, Yum
Users might like to submit their own experiences of the distro. What they liked, hated and had problems with.