Microsoft is planning to release a Community Technology Preview (CTP) of Windows Server Code Name "Centro" in the next few weeks. We look forward to your continued participation with Windows Server "Centro" and are really excited to receive your feedback on the upcoming CTP.
Windows Server "Centro" is built on Windows Server 2008 and provides an integrated server and management system for midsize businesses. The upcoming CTP includes many new Windows Server 2008 Beta 3 based components, as well as updates to the server applications that shipped in Windows Server "Centro" Beta 1 (updated versions of System Center Essentials 2007, Exchange Server 2007 and ISA, as well as new updates to setup, Active Directory domain join functionality and a host of other improvements).
Source:→ TechlogMicrosoft, Windows Server Centro, CTP, Previews