HDRI / Spherical Images display in view port? I have seen a video where it look like you can take an HDRI spherical background and use it as the background in the view port. It even rotates with the camera. 

The question is how do I set this up? I have even gone as far as pause the video but I do not seem to have the right "Nodes." Where is this world node? Where is this texture coordinates node? I am using cycles engine. Is there a step by step for version 2.73 that shows how to set this up and show in the view port?
The exact same can be accomplished by selecting the world tab in the properties editor, clicking use nodes, and setting the color to environment map. You will still need to open the file location.