A good friend of mine just told me that it was possible to listen to
conversations within earshot of a turned off cellphone, provided you
had the right software. He takes his cellphone battery out of the
device every night when he gets home also.

He doesn't strike me as someone who'd wear a foil hat, but he was dead
serious. I did a google and there are sites listed for such, but I'm
having my doubts.

What do you guys think?