GeoNames is YAG (yet another geocoder), but behind the curtains lie many cool features. The most unique of which is a reverse geocoder.

Reverse geocoding is converting Latitude & Longitude to a place name. This is the other side of the mirror from traditional geocoding, which converts a place name into latitude & longitude. Why would someone want to reverse geocode you ask? With reverse geocoding you can convert your GPS tracklogs into meaningful locations easily, or allow users to click on a map and get back actual location of where they're clicking.

The GeoNames API provides an interface for getting nearby postal codes, country, or most specific: place names.

Example

HighEarthOrbit offices: http://ws.geonames.org/findNearbyPlaceName?lat=42.4266&lng=-83.4931&style=full

returns:

  

    Northville

    42.43111

    -83.48333

    5003956

    US

    United States

    P

    PPL

    city, village,...

    populated place

6360

    252

    MI

    Michigan

    

    

  

The whole geo-enchilada

Lastly, to make you really feel warm and good inside, the GeoNames database is provided for direct download under a Creative Commons Attribution license. Yum, free data.

See the GeoNames Blog post about it.