The new clusterer Fluster2 provides marker clustering in Google Maps v3 just like MarkerClusterer did for v2.
Everyone knows the pain of displaying a lot of markers in a Google Map. For this problem there is MarkerClusterer which merges multiple markers to one cluster marker if there are a lot of markers at one place - as long as you use Google Maps v2. We used MarkerClusterer in our Social Intranet Solution too but wanted to migrate to Google Maps v3. So we had to write our own clusterer logic or adapt MarkerClusterer to work for v3. The result is Fluster2, a new clusterer built from scratch but based on the same logic as MarkerClusterer.
This is a screenshot of a map displaying 200 markers in Africa/Europe. As you can see, Fluster2 combines them to a much lower number of markers and shows the marker count, just as MarkerClusterer does. We are using the same images as MarkerClusterer by default. You can try the live demo of this example here.
You can download Fluster2 here.
Fluster2 is released under the LGPL license, so you're free to use it in any application.