BB FANS

It should come as no surprise that cellphone calls may be tapped by law enforcement.

But authorities also can use cellphones to eavesdrop on suspects, even when the devices are off.

The FBI converted the Nextel cellphones of two alleged New York mobsters into “roving bugs,” microphones that relayed conversations when the phones seemed to be inactive, according to recent court documents.

Authorities won’t reveal how they did this. But a countersurveillance expert said Nextel, Motorola Razr and Samsung 900 series cellphones can be reprogrammed over the air, using methods meant for delivering upgrades and maintenance. It’s called “flashing the firmware,” said James Atkinson, a consultant for the Granite Island Group in Massachusetts.

“These are very powerful phones, but all that power comes with a price. By allowing ring tones and stock quotes and all this other stuff, you also give someone a way to get into your phones,” Atkinson said.

RINF

Its also easy to switch on the speaker in any landline telephone and just listen in.

The government do it all the time to people.

Calrissian: does not own the magic black box

There's firmware for the Nokia 3310 which allows it to be controlled remotely without it appearing to be active.
It mainly allows the person at the other end to listen in.
Unlike the modern phones it doesn't has GPRS to report it's position back.

I did read that it's a requirement in the US for all current phones to have GPRS for they say to help locate you in an emergency ! But I think it's more for the government agencies to monitor it's citizens.

You can be located using the old method of triangulation using the phone cells. The more cells your in range of the more accurately your location can be found. This can be used when someone disappears as there is a record held of which cells you were in range of when your phone is turned off so the last known location of the phone when it was turned off or the battery failed is recorded.