In action movies, there always seems to be someone tapping a cell phone or listening in on someone else's private calls. But does that ever actually happen in real life? The truth is, the more of our lives that are put on our cell phones, the more likely they are to be used as targets for surveillance. Whether you're a parent wondering what your teen is up to, or you're a spouse who has questions about a loved one's actions, you might be tempted to use cell phone monitoring software. But before you take action, make sure that what you're doing is actually legal. In some cases, your actions may constitute an illegal invasion of privacy.

Data collection. If you're the main person on a cell phone account, there's nothing stopping you from contacting your cell service provider and asking for a breakdown of texts and numbers called. That's your right as a primary account holder, and you can't be prosecuted legally by checking up on someone else through your own account. You can get tons of information from just monitoring your account, including the numbers most often called and texted, and how much time is spent on each call.

Location services. Certain apps can be installed on a phone so you're able to use the installed GPS as a way to pinpoint exactly where the phone and its user are. Tracking someone in this way is not illegal, but it could be seen as stalking or harassment if you're using the information in an abusive manner. The safest way to proceed is to alert the person that you will be tracking their movements. This way you won't create any issues with privacy or cause irreparable damage to the relationship.

Recording. Recording phone calls as a method of surveillance is a slippery slope. In some states, it's illegal to make an audio recording of someone's voice if they are unaware, so you'd need a verbal affirmation in order to start recording. You can check privacy laws in your state to find out the law where you live. Otherwise tapping or making audio recording of someone's voice could very well land you in hot water, legally speaking.

Government surveillance. In most cases, the rules do not apply when government agencies are doing the cell phone surveillance. Law enforcement doesn't currently need permission or a warrant to begin cell phone surveillance. It's important to remember that if your surveillance is not sanctioned by law enforcement, you could become legally responsible for an invasion of privacy. The only way to legally spy on someone via cell phone is if you ask permission first.