PS modules download

Hello all

 I'm totally newbie in  windows power shell. Please bear with me.

I 'm using windows 7 and by default installation, it installs power shell either 1.0 or 2.0.

I wanted to use latest power shell which is version 4.0 mentioned in msdn web site.

I downloaded and installed .NET framework 4.5.
then downloaded and installed Windows Management Framework 4.0

both installation went well without any issue.

Now how can I verify if I'm using the ps version 4.0???(cmdlets to verify version)

and How and where can I download modules for ps?? (such as  showUI)

Please put a link for downloading ps modules for making a Forms, etc with ps.

regards