Since using a regular RFID-enabled credit card isn't flashy enough, you'll soon be able to slip your iPhone into a special Visa payWave case along with a memory card and simply wave it at cash registers to pay for things:
The technology will be possible thanks to a protective iPhone case that will include a secure memory card that will hold Visa's contactless payment application, called Visa payWave. The application, which is compatible with the iPhone 3G and iPhone 3GS, can be password protected and includes advanced security technology to uniquely identify each contactless transaction.
Supposedly the same sort of memory cards and cases should work with other smarthphones as well, but we'll hopefully know more about the technology this winter. [Apple Insider]
Picture by BigBeaks