eek! The beta for SP2 of Windows Server 2008 and Windows Vista showed up last week, I'm running SP2 beta for Vista - X86 and X64 with no issues. Get yours here. If you were wondering, as I was, here's a FAQ on SP2 for Windows Server 2008:
When did you release Service Pack 1 for Windows Server 2008? Why is this there a second service pack for Server 2008 which had no SP1? Server08 released with the Service Pack 1 code included, and was marketed as Server08 with SP1 already included. SP2 is the first post-release Service Pack for Server 2008.