GeoNames
Über den Artikel Real Web 2.0: Open, geographic information systems at Geonames.org bin ich gerade auf GeoNames.org gestoßen.
The GeoNames geographical database is available for download free of charge under a creative commons attribution license. It contains over eight million geographical names and consists of 6.5 million unique features whereof 2.2 million populated places and 1.8 million alternate names.