For non-GPS enabled phones, the trick is the cell phone towers themselves. The towers are in a known location, and based on triangulation of the signal strengths from the towers received, a estimate is made about where you are located.

Here is a wikipedia article that roughly describes one method of triangulation.

Cell tower triangulation would be a good search term. Another interesting location based service that recently came out of beta is Yahoo’s Fire Eagle which allows you to selectively broadcast your location to applications and friends.

A few days ago, I was surfing the web and I found out a project that works over most mobile phones which lets you know where your friends are in real time and update your status in twitter. It´s called Dimdix.

On their website they say you don´t need a GPS system to detect your location. Does anyone know how this works?

I´m using a Motorola L7 and amazingly it detected my location.

I cannot stop thinking of all the things I could do with it.

If anyone wants to take a look you can go http://www.dimdix.com

Thanks,

Regards,

Juan