Spatial Solr Plugin for Lucene and Solr
With the continuous efforts of adjusting search results to focused target audieces, there's an increasing demand for incorporating geographical location information into the standard search functionality. Spatial Solr Plugin (SSP) is a free, standalone plug-in which enables Geo / Location Based Search, and is built on top of the open source projects Apache Solr and Apache Lucene.
This plugin is very useful if you want to provide location based search in your application. Source code: http://code.google.com/p/spatial-search-lucene/