It basically serves as a sound deadener and a heat shield. MAKE SURE YOU WEAR SOME KIND OF GLOVES when you take it off. It has fiberglass insulation inside and if you get that stuff on your hands, you're gonna be itching for a few days.
Anyway, you'll notice that there are little round black clips holding the pad on to your hood. You can either take a flat head screwdriver and pry them off (be very careful that you don't scrape your paint), or use a door trim removal tool. You can get one of those at Pep Boys also for like 5 bux. Now, when you go to add the mirror film, some people have actually done it with the hood still on. I find it ALOT easier to do with the hood off. Have a friend help you with the removal of the hood.
When you lift the hood, you'll see 2 bolts on each side, holding the latches to the hood. The latches are up near the wiper cowl near the fender. Undo 1 bolt on each side at a time. Then once you undo both, grab the hood so that it doesn't fall on you, and lift it up and off the car. This is where a friend comes in hand.
Take the hood and lay it on a soft surface, like blanket or something. I laid mine down in the grass and it was fine. Then just cut out the mirror film in a general shape of the holes, and apply like window tint. After it starts to dry a little, take your blade and trim the edges carefully.
Good luck! <img src=icon_smile_cool.gif border=0 align=middle>