Earth. Open Street Map - wiki-based user created street maps. Have you ever wondered why smartphones like Blackberries and iPhones don't provide turn-by-turn directions in their Google Maps programs?
The answer is probably not what you think. It turns out that the map imagery that is used in Google Maps has licensing restrictions against it, preventing it from being used for turn-by-turn directions. Cartographer: Thematic Mapping For Google Maps. Thematic maps are very useful when describing statistical data about places.
The data, simply, becomes much easier to understand. Cartographer is a JavaScript library for creating thematic maps on Google Maps which supports custom styling. It is only a one JavaScript file that relies on the powerful Raphael.js vector-graphics library. It supports 3 visualizing types: GMap.NET - Great Maps for Windows Forms & Presentation.