_root.tweenBlur = function(my_mc, fromBlur, toBlur, duration, afterFunc){
	var blur:BlurFilter = new BlurFilter(fromBlur, fromBlur, 3);
	my_mc.filters = new Array(blur);
	blurTween = new Tween(blur, "blurX", _root.easeType, blur.blurX, toBlur, duration, true);
	blurTween.onMotionChanged = function() {
		blur.blurY = blur.blurX;
		my_mc.filters = new Array(blur);
	}
	if(afterFunc) blurTween.onMotionFinished = afterFunc; // This will run a function when the blur is complete
}

Flash blur action

flash

ActionScript