geography with PHP

[flapjack50]

Does anyone know of an extension or something that will provide me with geography related information? For instance, I am working on a web site that will let people find others in their surrounding area. I would think the best way would be for them to enter in their zip code and this would start searching out through the surrounding zip codes (or for x miles out) for a person in their area. I have seen this in web sites before but was wondering how they did it.

[LiLcRaZyFuZzY]

Where are you living? In the USA?
How is the zip-code syntax there?

[bokeh]

Basically you need a database of postal codes that contains lat/long coordinates. You can then easily search the database for other entries within a certain number or fraction of degrees of queried location.

[purefan]

and I bet that when a new user signs up in the site a requested field is at least the state where he/she lives, internally in a db the system is able to determine how far each user is from one another, am I right?

[SpectreReturns]

A couple months ago there was a big thread on how to do that, you might care to search for it.