It appears that because of the way Microsoft labeled its PowerShell 2.0
download package, there is a bit of confusion on whether the technology is available for download or not. The short answer is yes, PowerShell 2.0, the version that is included by default in Windows 7 and Windows Server 2008 R2 has already been wrapped up and is indeed offered to users of older versions of Windows client and server platforms for quite some time now. The confusion has been spurred by the fact that PowerShell 2.0 is not offered as a standalone download, but rather as a part of a larger package dubbed the Windows Management Framework.
"We are responsible for the confusion because our redistribution is not called PowerShell V2, it’s called Windows Management Framework,” noted Jeffrey Snover
[MSFT] distinguished engineer. Along with PowerShell 2.0, the Windows Management Framework brings to the table two additional technologies, namely Windows Remote Management (WinRM) 2.0 and Background Intelligent Transfer Service (BITS) 4.0.