This post comes as courtesy of Chrissy LeMaire and Carlos Perez. PowerShell is already shipped with Windows Operating System. Since it was released 10 years ago, different versions of PowerShell have been shipped through different versions of Windows. You could also upgrade to another version by installing Windows Management Framework. It would be quite useful to know what version of PowerShell is shipped with what version of Windows and up to what you can upgrade to get most out of it.
Carlos Perez was able to spend some of him time and put together a nice matrix about it, which you can see below:

This is quite a handy and useful list for use.