How to "do something" based on location

Hello,
I've written an app that detects my location and posts it to a server. It works fine. Let's call this app 1.

Now I'd like to write a background service that launches app 1 when the device is located in a specified location, which will be held in the device's database.

Can someone point me to examples or information on how to create a background service that runs automatically when the phone is turned on? Also if anyone has seen articles on how to efficiently implement this that would be helpful. (For example, if the device is a hundred miles from the nearest location of interest, it should sleep for some logical amount of time before checking the it's location again.)

Thanks...

 

This page (http://developer.android.com/guide/topics/location/index.html)states this:

Once your application has a LocationManager, your application is able to do three things:
(I omitted the first two things, as they're not what I'm interested in)

Register/unregister for a given Intent to be fired if the device comes within a given proximity (specified by radius in meters) of a given lat/long.

But I've not seen how to do this yet...

 

Never mind, I found some info after googling proximity alert.