Cell phone privacy
Q. Is it possible for someone to listen in on my cell phone call?
A. Possible but not practical. Today's digital cell phones are nearly impossible to monitor. Certain federal intelligence agencies and the wireless carrier itself might be able to listen in but even then it would be extremely difficult. Let's not consider, then, targets of the FBI or CIA. What about ordinary folks?
Wireless to wireless calls
All digital phones like GSM/PCS types, ones that use a smart chip, are essentially impossible to monitor over the air. They use a strong encryption scheme which encodes voice traffic flowing between the mobile and the cell site. Two people communicating with each other, each using a GSM/PCS phone, should have little to worry about. Older analog cellular telephones, though, can be easily monitored with a scanning radio or another cell phone, one that's been modified to do that. This brings up a problem: you both may have a digital phone, but they may not be operating in digital mode. (continues here -->)