This is a equivalent to add movie to the stage
Equivalente de utilizar loadMovieNum as2 a urlLoader en as3

var urlRequest:URLRequest = new URLRequest("movie.swf");
var urlLoader:Loader = new Loader();
//Load the swf
//Carga el swf al objeto
urlLoader.load (urlRequest);
//Show the swf on the stage, also you can add the object to othe movieclip or sprite, just changing stage for the object of movieclip
//Lo despliega sobre el stage
stage.addChild (urlLoader);

For unload the swf