PowerShell v2 for Vista and Server 2008 has been released as RC

You can now get PowerShell v2 as a download for Windows Vista and Windows Server 2008 from Microsoft Connect.

Windows XP and Windows Server 2003 SP2 are not included in this RC release but they will be made available in future.

For more information, and download link, see the PowerShell team blog announcement.

http://blogs.msdn.com/powershell/archive/2009/08/14/powershell-2-0-for-windows-vista-and-windows-server-2008-release-candidate.aspx