Storing and Querying GPS Coordinates Effectively

Question

I want to create a large database of GPS coordinates that can be queried by saying \"Return all coordinates that are within \'n\' metres of [this coordinate]\".

I need i

Answer 1

Following up on Erich - if you have your choice use PostGIS (postgresql) it's free and open source, does the queries you are describing very very quickly, runs on almost all platforms, and did I mention it is free?