I found a nice web service that provides a JSON array of places based on a latitude and longitude. It is provided by GeoNames and has been very useful supplying locations for my Ruby on Rails app.
Place this URL in your browser or click the link:
Here is a sample JSON output for one location:
I also found a nice Rub Gem called geonames that provides a nice, easy to use module with classes.
Look here for more information on the GeoNames web service: http://www.geonames.org/export/JSON-webservices.html#citiesJSON.