Paul Thurrott's SuperSite for Windows has posted a preview on Windows Server Longhorn

Recently, several representatives from Windows IT Pro Magazine received a briefing about the Beta 1 version of Longhorn Server, the next member of the Windows Server family, currently due in the first quarter of 2007, or about six months after Windows Vista ships in late 2006. There was just one condition for this briefing: Our non-disclosure agreement (NDA) was "permanent," which was a bit unusual. The problem, we were told, was that Longhorn Server Beta 1 included just a tiny subset of the features Microsoft was planning for the final release. The company didn't want to disappoint anyone, noting that the Beta 1 release was more of an alpha-quality build and not a true beta.

Longhorn Server Preview 2: A Look at Windows Server Longhorn Beta 1 and Community Technical Preview