Mine

mcCheck.onRollOver = function()
{
	showToolTip('asdf');
}
mcCheck.onRollOut = function()
{
	hideToolTip(tooltip);
}
function showToolTip(aText:String)
{
	var tmp:MovieClip = attachMovie('tooltip','tooltip',_root.getNextHighestDepth(),{_alpha:0});
	pad = new mx.transitions.Tween(tmp, "_alpha", mx.transitions.easing.Strong.easeOut, tmp._alpha, 100, 1, true);
	trace(tmp);
	tmp.onEnterFrame = function()
	{
		this._x = _root._xmouse - 10;
		this._y = _root._ymouse - 10;
	}
}
function hideToolTip(target:MovieClip)
{
	trace(target);
	target.removeMovieClip();
}