Waypoint System

I want to add a waypoint for location detection(e.g. if my car passes a set point, a GUI Texture pops up). How can i create that, and anyone know a tutorial, or if you can create a tutorial…

Create game object, add BoxCollider, set to ‘trigger’, add script that handles OnTriggerEnter, place object where you need it.

A tutorial with a waypoint system can be found here:
http://www.gotow.net/andrew/blog/?page_id=78