class ContentLoader extends MovieClip
{
    public function ContentLoader ()
    {
        loader = new Loader();
        loader.addEventListener('complete', onComplete);
    }
    private function onComplete(event:Event)
    {
        dispatchEvent(event);
    }
}
//-----------------------------------------------------
var l = new ContentLoader()
l.addEventListener('complete', onComplete)
function onComplete(event:Event)
{
    trace('contentLoader is ready');
}