Hey, Scripting Guy! How Do I Check Which Version of Windows PowerShell I'm Using?

Hey, Scripting Guy! With the release of the Community Technology Preview (CTP) 3 for Windows PowerShell, some of our staff have gone ahead and updated their computers. I am now beginning to worry that I need to check the version of Windows PowerShell that is installed on a computer before I run a script. I have two questions, the first of...