ActionScript 3.0 :: Flash - How To Flip 2D Character When Moving

I have a mc called boy and I have an instance of that mc called boy_mc. I have figured out how to make his position change on the stage, but I cannot figure out how to do some other things.

Here is the code that I have so far:
import flash.events.KeyboardEvent;
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
function keyPressed(evt:KeyboardEvent):void{
switch(evt.keyCode) {
[Code] .....

I am trying to learn 3 things.

1. How do I make him be facing left when I push left and facing right when I push to right?
2. How to I restrict him to a certain area of the stage? I am going to have some buildings on the top and I don't want him to be able to walk past the street level. So basically I don't want him to be able to go off the stage or up some to be determined height.
3. When he walks up and touches a door on my stage, I want to jump to another place in the timeline.