This may sound strange but I just saw a guy on TV clean the headlights with some toothpaste. Put the toothpaste on a rag and apply to the headlight lenses in a circular motion. It really removes the foggy look on the lens. If you do this, let us know if it works since I am waiting for an opportunity to try this trick. Good luck.
If you want to get the insides clean you have to bake your headlights apart (heat it up enough that the silicone holding them together gets soft and you can pull them apart). I used this link when blacking out my headlights. You obviously don't really need most of the directions, but it should help in the department of pulling apart and putting back together. http://www.clubwrx.net/forums/showthread.php?s=&threadid=14169 I think that you have a newer car, but it should still be very similar.
I wouldnt really advise cleaning the inside, odds are they're not dirty. In fact, if they've never been opened before its impossible for them to be dirty. If you do open them up and clean the insides you must, and I cannot stress this enough, use an extremely soft (non-abrasive) terry cloth, etc, to do so. Anything else will give you the present of small scratches everywhere... Now, to clean the outside there are a variety of ways it all depends on how much time you want to devote, etc. People rarely seem to take great care of their lights...If you are washing your car, spend a few minutes washing them as well. Never use an amonia-based cleaner (windex) on them as you run the risk of splotching the lexan (making nasty spots). Follow that up with a nice dose of a plastic polish. Then buff on some wax perhaps, or whatever you prefer. I generally use this method to touch up, repair, or refresh customer lights or core swaps. If your lamps are oxidized (not clear anymore) there are several methods to fix that as well.
^ yeah actually much better advice. I just wanted to give you the info on how to open them, if you so desire.