Cell phones are encrypted with low level encryption...so the story is false.
http://security.stackexchange.com/questions/35376/are-phone-calls-on-a-gsm-network-encrypted
You used to be able to scan analog cell phone calls, which is what Newt’s phone was back then. Remember, that was back in 1997.
Today, you can intercept GSM and CDMA cell phone calls, but the equipment is expensive, or you have to know what you’re doing and do some hacking yourself.
This isn’t rocket science.