From Neowin:
"The test version of Windows Server 2003 R2, which is built atop the code from the SP1 release of last month and supports both 64-bit and x86 systems, sports streamlined versions of several management systems, including branch and remote server management, access management and storage management.
Try Windows Server 2003 R2, the update version of the award-winning Windows Server 2003 with Service Pack 1 (SP1), that extends your connectivity and control.
View: Register to download the beta software
View: TechNet Windows Server 2003 R2 TechCenter"