The original consumer contactless payment system which has been around for years is Exxon/Mobil's Speedpass. If you sign up for an account they send you a little fob for your keychain that when you hold it up to the Speedpass sign at the gas pump it bills the credit or debit card you have on file - slightly less work and faster than swiping a debit or credit card because there's no signing or PIN.
In the last year or so MasterCard has begun to roll out its system for contactless payments called PayPass. Special debit/credit card readers have been installed at participating merchants such as Duane Reade, McDonald's and CVS among others. MasterCard issues special credit cards with RFID chips in them or you can get a special fob for your keychain if you already have a MasterCard and don't want a new credit card (like me).
Now MasterCard is working on embedding the technology into mobile phones, as has been done in Japan for some time. I read about the official press release detailing the joint plans of MasterCard, Citigroup, Cingular and Nokia to test this out in NYC. I was already aware of the project, though not in the full details, as we have been talking with some of the parties about participating in the content downloads to mobile phones. One piece of info that I didn't see mentioned on any of the blogs covering the story is that the phone being used for the trial is the Nokia 6126. This is essentially the same phone as the Nokia 6133 sold by T-Mobile except that it has the NFC (near-field communication) technology.