preloader su un solo frame:

codice:
this.stop();

createXML = function()
{
	this.mioXML = new XML();
	this.mioXML.load("file.xml");
	this.onEnterFrame = xmlPreloader;
};

xmlPreloader = function()
{
	var car = this.mioXML.getBytesLoaded();
	var tot = this.mioXML.getBytesTotal();
	if(car == tot){
		delete this.onEnterFrame;
		this.play();
	}
};

moviePreloader = function()
{
	var car = this.getBytesLoaded();
	var tot = this.getBytesTotal();
	if(car == tot){
		this.onEnterFrame = undefined;
		this.createXML();
	}
};

this.onEnterFrame = moviePreloader;