Listening devices or spyware installed on your cellphone can allow anyone to listen in on your private conversations and track your exact location. Some spyware sends text messages to the listener, informing him exactly when you are using your cellphone. Keep your cellphone with you at all times to reduce the chances that someone will install a listening device on it. If you think your phone's been tapped, listen for unusual noises and other abnormalities that might indicate a listening device.
Turn your phone off and keep it off until the battery cools. Touch the battery about once an hour while the phone is off. If it warms up, someone may have tapped your cellphone.
Call a friend with your cellphone and have a conversation with him. During the call, keep an ear out for any unusual noises. You may hear an abnormal beeping or clicking noise if your phone is tapped. You may also hear a buzzing sound.
Monitor your cellphone while it is on. Cellphones that have a listening device may light up at unusual times, even when you haven't made a call or received a text message.
Turn your phone off and monitor the display. It may turn on and flash a light briefly if someone is trying to access the phone remotely.
Record the number of times, if any, that you have answered the cellphone and nobody responded. Sometimes, a tapped cellphone may ring, but no one is on the line.
Call your cellphone company and ask them to check for a listening device or software. The company cannot tell you if there is a legal wiretap on your phone, but they can inform you if it is an illegal wiretap. They will also contact the authorities.