Spatial Search With Apache Solr and Google Maps by Wern Ancheta.
From the post:
In this tutorial I’m going to show you how to setup spatial search in Apache Solr then were going to create an application which uses Spatial searching with the use of Google Maps.
You will also learn about geocoding and JQuery as part of this tutorial.
For the purposes of this tutorial were going to use Spatial search to find the locations which are near the place that we specify.
If you have a cellphone contract or geolocation you can find who lives nearby. 😉
Assuming you have that kind of data.