Go to the following page to read more about Windows Server 2003 Service Pack 1 (SP1) Release Candidate 2(RC2) and instructions on how to download it. This version of the software is intended only for installation in a test environment. We advise against installing and evaluating beta software on any production computers.
It is a good time to install and test your environment so that the RTM deployment goes without any glitches. It will also give you a headstart to making sure that all your applications are working fine with the new security features. This page also has a link that lists Top 10 reasons to install Windows Server 2003. There's another link that talks about the New Networking Features in Microsoft Windows Server 2003 SP1.
RTM is not too far away either.