[CrazyFlasher]

var vx:Number;
var vy:Number;
var d:Number;
var speed:Number = 5;
var target:MovieClip = _root;

mc.onEnterFrame = function(){
	vx = target._xmouse - mc._x;
	vy = target._ymouse - mc._y;
	d = Math.sqrt(vx*vx + vy*vy);
	
	smooth();
	if(Math.abs(mc._x - target._xmouse) > 5 || Math.abs(mc._y - target._ymouse) > 5){
		mc._x += vx / d * speed;
		mc._y += vy / d * speed;
	}
}

function smooth(){
	var newD:Number = Math.sqrt((mc._x - target._xmouse)*(mc._x - target._xmouse) + (mc._y - target._ymouse)*(mc._y - target._ymouse));
	speed = newD / 10;
}

накидал по-быстрому вроде работает