Is there a method to track specific cell phones? That's the general question but specifically I am looking to see what may be available to track, from my iPhone, other phones that are on my family plan. I don't care if it is something that can be turned off or on by the user of the phone as it will be primarily a trust based issue. My son and daughter both have a habit of going off on bike rides or runs (with their phones) and then not answering the phone when called. My son has a smart phone (droid based) while my daughter just has a regular phone (LG EnV touch).