Windows PowerShell RC 2 is now available for Windows XP SP 2 and Windows 2003 Server SP 1. Release Candidate 2 adds direct support for ADSI and improves support for WMI.
If you are currently using an older version of PowerShell, you need to uninstall it before installing this version. This version is only available in English.
Microsoft is currently planning on a Q4 web release of the final version.