div#links a span {display: none;}

div#links a:hover span {display: block;
   position: absolute; top: -10px; left: -10px; width: 600px; height:460px;
   padding: 5px; margin: 10px; z-index: 100;
   background: white;
   font: 10px Verdana, sans-serif; text-align: center;}