The second step is actually having the service doing something (locating). This happens when you press the little blue "locate me" on the map. If you don't unclick this, even if you leave the map application ,the GPS is still up and running and listening to teh signals from the satelites, and that sucks power down hard. The only option to turn this off is to either uncheck the blue locator orb, or go into settigns and completely disable the service.
If you turn the service on, but NEVER go into the map application and hit the orb to initiate tracking, you're not really using any battery.
Thanks so much!! I never knew that! Hopefully that'll save me some battery now