I'm not that up on CentOS so I'd be curious to know if it is possible to upgrade CentOS 5.2 to 5.3 without reinstalling? Perhaps via Yum? Or can you get update RPMs?
Once CentOS 5.3 is released, you can just type "yum upgrade" and you will be upgraded from CentOS 5.2 to CentOS 5.3.