Geonames web Services

The GeoNames geographical database is a database available for download free of charge. It contains over eight million geographical names and consists of 6.5 million unique features of 2.2 million populated places and 1.8 million alternate names. The data is accessible free of charge through a number of webservices and a daily database export. Some of the webservices include findNearbyWikipedia which allows you to search wikipedia articles based on longitude and latitude.The data is collected from over a hundred different data sources.GeoNames is already serving up to over 11 million web service requests per day. Its great for map based mashups. Output includes JSON and XML. check it out