Take a look at Geonames.org
It's a free webservice that allow you to get a lot of informations from a long/lat
They also provide a free (and open source) Java Client for GeoNames Webservices library (library for other language also provided: ruby, python, perl, lisp...)
Here's some info you can get from long/lat: (complete list of webservices here)
- Find nearest Address
- Find nearest Intersection
- Find nearby Streets
- Elevation
- Timezone
