Re: Locating other phones? GPS Apps...
Sign everyone up for a different Google Account. No need to use it, just sign up and login once.
On each phone, go to
Download and run Google Maps for Mobile. Once you can see you blue dot (you may need to stand outside for 10 mins), Options=>Latitude, sign in with your (individual) Google Accounts. Then add each other.
The Droid will already have this installed; as will the MyTouch. For iPhone because of lack of multitasking, you could only see updates from your Dad if he had the latitude app open. BB is well supported by Latitude.