Go to walmart and buy the DIN tools for popping the stock HU out. They are about 4 inches long and in the shape of a "U". There should be two in the package. Take them and put them in the holes on the sides of the HU. Push them out(towards the doors) and pull the HU right out. You can also buy the wire kit for the HU at walmart or radio shack. Make sure it is for "premium" sound there should be 3 cables total.
If you need more help or this doesn't make sense just post again.
In the words of HonkeyTonkMonkey: Once you take out the stock head unit make sure you poop on it then give it to some circus midgets and tell them to eat it because circus midgets like poop.
