[subhumanderelict]

I am currently using Sprite Terminator. It's pretty cheap and works fairly well for me. Granted, I'm not using it to keep track of people, so I'm not using it nearly as much as you would be, but after experimenting with it a few times it proved itself worthy of keeping.

One thing though: If you do use it, make sure to delete the link from the Programs list on their phones. That way, once you install it, they won't know it's there unless they go into the Program Files folder. It doesn't show up in the Remove Programs list and accessing the program itself requires a password. Also, when you send the command to retrieve someone's coordinates, all that will happen is their screen will activate, but nothing will come up.

The only problem is that you must send the command from a phone. It won’t respond to an e-mail sent as a text message.