var map = '';
var baseIcon = new GIcon(G_DEFAULT_ICON);
baseIcon.shadow = "http://www.google.com/mapfiles/shadow50.png";
baseIcon.iconSize = new GSize(20, 34);
baseIcon.shadowSize = new GSize(37, 34);
baseIcon.iconAnchor = new GPoint(9, 34);
baseIcon.infoWindowAnchor = new GPoint(9, 2);

function createMarker(point, html) {
  var marker = new GMarker(point);
  GEvent.addListener(marker, "click", function() {
    map.openInfoWindowHtml(point, html);
  });
  return marker;
}

function createMarkerLetter(point, html, letter) {
  var letteredIcon = new GIcon(baseIcon);
  letteredIcon.image = "http://www.google.com/mapfiles/marker" + letter + ".png";
  markerOptions = { icon:letteredIcon };

  var marker = new GMarker(point, markerOptions);
  GEvent.addListener(marker, "click", function() {
    map.openInfoWindowHtml(point, html);
  });
  return marker;
}