After continued developer requests, Google has added marker clustering to Google Maps SDK for iOS Utility Library. The feature allows users to populate maps with a large number of markers while keeping the map clean and readable. As zoom levels adjust, markers aggregate and slit out accordingly.
Google has just introduced a new Enterprise Service, "Google Maps Coordinate", a web and mobile application that helps businesses manage and improve the efficiency of their mobile workforce. You can check out the Google Coordinate API here.