Paul Thurrott has published a Windows Server 2003 R2 FAQ

Microsoft's Windows Server roadmap has been in constant flux for years, with plans for Blackcomb and Longhorn versions of Windows Server now pushed back ever further to make room for an interim Windows Server 2003 update dubbed Windows Server 2003 R2 ("release 2"). First revealed here on the SuperSite for Windows, R2 will include all of the free out-of-band updates Microsoft shipped for Windows Server 2003 since April 2003, including the Group Policy Management Console and Windows SharePoint Services.