Quick test for getting the angle from the accelerometer.

SkateOrFall.as

package  
{
	import flash.display.Sprite;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.events.Event;
    import flash.events.AccelerometerEvent;
    import flash.geom.Point;
    import flash.sensors.Accelerometer;
    import flash.text.TextField;

    /**
	 * @author jessefreeman
	 */
	public class SkateOrFall extends Sprite
	{


        private var ball:Sprite;
        private var accelerometer:Accelerometer;
        private var xSpeed:Number = 0;
        private var ySpeed:Number = 0;
        private const RADIUS = 20;
        private var tf:TextField;
        private var needle:Sprite;
        private var distancePoint:Point = new Point(0,-100);

		public function SkateOrFall()
		{
			
			stage.scaleMode = StageScaleMode.NO_SCALE;
            stage.align = StageAlign.TOP_LEFT;

            createBall();

            if (Accelerometer.isSupported)
            {
                accelerometer = new Accelerometer();
                accelerometer.addEventListener(AccelerometerEvent.UPDATE, accUpdateHandler);
                stage.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
            }

            tf = new TextField();

            addChild(tf);

            createNeedle();
		}

        private function createNeedle():void
        {
            needle = new Sprite();
            needle.graphics.clear();
            needle.graphics.lineStyle(6, 0xff0000);
            needle.graphics.lineTo(0,0);
            needle.graphics.lineTo(distancePoint.x, distancePoint.y);
            needle.graphics.endFill();
            addChild(needle);
            needle.x = (stage.fullScreenWidth *.5) - 3;
            needle.y = stage.fullScreenHeight;
        }

        private function updateNeedle():void
        {
            var x:int = distancePoint.x;
            var y:int = distancePoint.y;

            var mousex = x-stage.fullScreenWidth * .5;
            var mousey = (y-stage.fullScreenHeight * .5)*-1;
            var angle:Number = Math.atan(mousey/mousex)/(Math.PI/180) - 90;
            if (mousex<0) {
                angle += 180;
            }
            if (mousex>=0 && mousey<0) {
                angle += 360;
            }
            tf.text = "Angle: "+angle;
            needle.rotation = angle*-1;
        }

		private final function createBall():void
        {
             ball = new Sprite();
             ball.graphics.beginFill(0xFF0000);
             ball.graphics.drawCircle(0, 0, RADIUS);
             ball.cacheAsBitmap = true;
             ball.x = stage.stageWidth / 2;
             ball.y = stage.stageHeight / 2;
             addChild(ball);
        }

        private final function enterFrameHandler(event:Event):void
        {
            event.stopPropagation();
            moveBall();
        }
        private final function moveBall():void
        {


            var newX:Number = ball.x + xSpeed;
            var newY:Number = ball.y + ySpeed;
            if (newX < 20)
            {
                ball.x = RADIUS;
                xSpeed = 0;
            }
            else if (newX > stage.stageWidth - RADIUS)
            {
                ball.x = stage.stageWidth - RADIUS;
                xSpeed = 0;
            }
            else
            {
                ball.x += xSpeed;
            }

            if (newY < RADIUS)
            {
                ball.y = RADIUS;
                ySpeed = 0;
            }
            else if (newY > stage.stageHeight - RADIUS)
            {
                ball.y = stage.stageHeight - RADIUS;
                ySpeed = 0;
            }
            else
            {
                ball.y += ySpeed;
            }

            distancePoint.x = ball.x;

            updateNeedle();
        }

        private final function accUpdateHandler(event:AccelerometerEvent):void
        {
            xSpeed -= event.accelerationX * 2;
            ySpeed += event.accelerationY * 2;

            //tf.text = "xSpeed "+ xSpeed;
        }
	}
}