This is scary stuff. It is just what you think it is. It is software you put on someone's laptop, cell phone, blackberry, etc and when they get a call, you get it, when they send an e-mail you get it. Basically it clones the device. You will notice that alot of the manufacturers state "...make sure you get permission before installing this on someone's device." Well you know people are not doing that. And in most states, use without permission is a crime.
In criminal investigations this technology is used but before it is implemented an independent review is done for both necessity and practicality, then a warrant must be obtained from a state or federal judge and the continued use has to be reviewed by a judge on at regular intervals to justify continued use.
IMO if you feel you need this to check up on your loved one then you should just move one. Using this in that regard is going to bring you nothing but bad news. Even if you discover nothing bad when they find out you have been snooping they will be pissed and you will get bad the bad news you were looking for. Just my opinion.
You can find it by googling bluetooth spy. Actually the site is cheesy and I wonder if the software really does what it claims to do.
If the software does work as described, it's likely illegal in the US because it would violate federal wiretapping laws. Just like installing a keystroke / surveillance software on someone's PC to illegally monitor them, for example abusive/jealous spouses. Some have gone to prison for that.
Bluetooth Spy help
