I've had my HTC Trophy for a year now.  Love it!  I've collected a modest amount of apps, one of the newest being MyWalk.  I want to start tracking my walking, distance, speed, etc.  It is my understanding that app uses location services (which makes sense), and I'm guessing it polls the location frequently.  That's OK, while I'm walking, but I don't want it doing that while I'm sitting at my desk working.  So, how do I shut it off, when I don't need it?