Who would have thought that your cell phone would become the place to store your credit card? It makes perfect sense to me now, but just like cameras in cell phones, I didn't see it coming.
NTT Docomo Inc. in Japan is testing contact-less card support in cell phones. The JR train lines in Japan have used contact-less cards (like those cards you wave in front of the computer room door) for a few years. Apparently now cell phones can emit this protocol. Here's an interesting overview.
And hey,it's a standard. ISO/IEC 18092. 10cm range using 13.56MHz according to an article in EE Times ("Japan Mobile Phones Test Transaction Tech"). Manchester encoding of a 212-kbit/second stream.
Apparently there are chips from a Sony venture, Felica Networks, Inc.
Docomo is calling it "Mobile Wallet".