With one of my recent projects I find out limitations on calling Google maps geocoder functions. Google prevents huge amount of requests. They allow only certain amount of requests per one time period (I was able to make 10 requests at once). To find out what was a problem and also fixing this task takes me a while, maybe this post save you some debugging (google-ing).
// some addresses for demonstration..
More sophisticated solution can be created by using Ajax (when you get latitude and longitude save it in DB or file system). It will be faster to get geo – locations data from DB than from Google geocoder requests..
23 queries in 0.244 seconds.