Дружно говорим спасибо silin`у.

Код AS3:
package silin.utils
{
import flash.display.*;
import flash.events.*;
/**
* отслеживание нажатых клавиш
* @author silin
*/
public class Key
{
private static var _keys:Array = [];
private static var _stage:Stage;
private static var _enabled:Boolean=true;
public static function register(stage:Stage):void
{
_stage = stage;
_stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
_stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
}
private static function keyUpHandler(evnt:KeyboardEvent):void
{
for (var i:int = 0; i < _keys.length; i++)
{
if (_keys[i] == evnt.keyCode) _keys.splice(i, 1);
}
}
private static function keyDownHandler(evnt:KeyboardEvent):void
{
var key:int = evnt.keyCode;
for (var i:int = 0; i < _keys.length; i++)
{
if (_keys[i] == key) return;
}
_keys.push(key);
}
public static function isKeyDown(key:int):Boolean
{
for (var i:int = 0; i < _keys.length; i++)
{
if (_keys[i] == key) return true;
}
return false;
}
public static function get lastPressed():int
{
return _keys.length ? _keys[_keys.length - 1] : 0;
}
static public function get enabled():Boolean { return _enabled; }
static public function set enabled(value:Boolean):void
{
if (_enabled == value) return;
_enabled = value;
_keys = [];
if (_enabled)
{
_stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
_stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
}else
{
_stage.removeEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
_stage.removeEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
}
}
}
}