It is relatively hard to tap and spy on mobile phone calls using traditional cracking and hacking techniques on the wire, but since cell and mobile phones contain more computer power than earlier, some software vendors have introduced applications to overcome the fairly hard problems related to wiretapping directly on the wire data transmissions.
BlackBerry spy software works by secretly recording BlackBerry cell phone events such as text messages sent and received, emails sent from the BlackBerry, and the phone's call history logs.
Have you ever wondered where your second half is going when they say they are going for a safari, or perhaps when you try to call someone, and they are not answering their phone, do you wonder where they are? If you do then you should get a cell phone tracker.
There are a group of researchers who have initiated The GSM Software Project. They aim to develop to share information and get others to collaborate on developing a scanner that can eavesdrop on GSM phone calls. The goal is to make an under $1,000 (USD) device and share information on how to build it. This project bears watching, simply because if relatively low-cost GSM scanners become available, it would definitely create a new threat model for GSM phone users.