How do I build a beer room/cellar? I've got an extra room in my house that I was thinking of turning into a "beer cellar", or as much of a cellar as an above ground room can be. I don't have a problem with the actual construction, but especially since I'm in Phoenix, Arizona, I was trying to figure out how to insulate and cool the room for optimum storage.

Also, should I build the shelves to store both 6 packs still in the original cardboard casings along with individual bottles, or should I plan to remove all bottles from packaging? Separate temperature control? Lighting considerations?

One final consideration, should I keep all bottles of similar size on separate shelves, or should I have more open shelves for more air flow around bottles?
You'll probably do best keeping the room layout simple and as easily organized as possible.  The main thing for the beer is to keep the temperature steady and relatively low (around 50F) and keep light out.  Even with brown bottles there's still some UV penetration, which you want none of.  So keep it dark when you're not in there and try to avoid florescent lighting when you're there.  Keeping it organized also helps you minimize your time in there, which keeps light and temperature steady.

I wouldn't worry too much about the air flow as long as it's not completely stagnant and all the areas of the room are getting some air of the right temperature.  Liquid and glass hold temperature a lot better than air on their own so they won't have significant fluctuation once you get them where you want them.  I think most collections prefer shallow shelves for this reason.