stop();
import caurina.transitions.*;
_root.onEnterFrame = function()
{
	trace("onEnterFrame");
	a = getBytesTotal();
	b = getBytesLoaded();
	percent = Math.round(b / a * 100);
	preloader_mc.status_tf.text = "Loading " + percent + "%";
	if (b >= a)
	{
		Tweener.addTween(preloader_mc, {_alpha:0, time:1, transition:"easeOutQuint", onComplete: onStartVideo});
		delete this.onEnterFrame;
	}
};

function onStartVideo()
{
	trace("onStartVideo()");
	preloader_mc._visible = false;
	gotoAndPlay(1);
}

Just shows the percentage of loaded file in a textfield and fades out the preloader, when loading complete.

Standardloader Flash 8 AS 2.0

ActionScript