I asked a similar question in another forum, but my situation has somewhat changed. Basically my wife and I want to keep an eye on our step son who seems to not want to follow any rule we lay down. I managed to talk my sister-in-law out of her 3GS to replace his 3G (so I can install iOS 5 on his "new" phone). But the real reason is that I want to enable the Find my iPhone app so that we can know where he is via GPS. Now when I fire up the app on my iPhone 4 it has my phone and my MBA that come up. My question is this...how do I add another phone onto my phone? I mean, literally describe the process to me step by step. Do I need to install this app on every phone that I want to keep track of? If not, does every phone I want to keep track of need a mobile me/iCloud account? Do I? Sorry for all the questions, but can't seem to find how this thing is supposed to work exactly. Or if this question has already been asked (and I have to believe it has), please direct me to that thread as I did a search and was unable to come up with an answer.