A simple javascript utility for clustering markers using the Google Mapis V3 API that allows you to style the window using CSS.
var mapOptions = {
zoom: 8,
center: new google.maps.LatLng(45.523452, -122.676207),
mapTypeId: google.maps.MapTypeId.ROADMAP
}
var map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions);
var i = 0;
while(i < 22) {
var marker = new google.maps.Marker({
position: new google.maps.LatLng(45.51991, -122.707844),
map: map
});
i++; }