function prepareLinks() {
  var links = document.getElementsByTagName("area");
  for (var i=0; i<links.length; i++) {
  if (links[i].getAttribute("class") == "popup") {
    links[i].onclick = function() {
      popUp(this.getAttribute("href"));
       return false;
      }
    }
  }
}

function popUp(winURL) {
  window.open(winURL,"popup","width=810,height=548,menubar=no,toolbar=no,resizable=yes,titlebar=yes");
}

YAHOO.util.Event.on(window, 'load', prepareLinks);