WSJ.com - Why Some People Put These Credit Cards In the Microwave
The good news is, MasterCard's PayPass credit cards include an embedded radio chip (RFID) that make it easier to pay. Instead of putting it through the swiper, you just hold it up two inches from the machine.
The bad news is that now there's a new way to steal your money. In theory, somebody with the right equipment could pull your info from your pocket while you are standing in a crowded elevator.
But the good news now is that an industry of counter-measure products is springing up. How about FoeBud, an online store that sells, among other things, radio-proof wallets.