It was almost two years ago that I wrote a post linking to an Engadget article that showed how someone could remotely access drivers' licenses and passports that are embedded with RFID chips. The featured video is at Engadget or here.
someone can access credit card information in your wallet without touching you.
To know if your credit card is susceptible, look for the symbol at the left.
Addendum: Some advice from Z. Constantine: "If you hold your RFID-enabled cards at an angle in bright light, you will be able to see a rectangular shape (approximately 3x6mm) opposite the signature line on the back: this is your RFID chip. Take a finishing nail and a hammer and put the nail through the chip. Done. Your card is still perfectly valid for transactions when swiped, but your RFID chip is disabled so the only swiping you need to worry about is the kind you're used to."