Using your iPhone as a membership card or even a plane ticket is nothing new, but soon you will be able to use it as a Visa card too. DeviceFidelity's In2Pay iPhone accessory, announced yesterday, is basically a paired case and app that allows you to simply whip out your iPhone and swipe it over Visa's PayWave consoles. PayWave is fairly common already--many grocery and retail stores use it, and I've played with it in my hometown at the Wawa deli chain (I mention Wawa because my barometer of how useful a new payment system is is heavily based on its ability to buy a hoagie).
Visa says it's expanding PayWave nationwide, to include previously underserved regions, and DeviceFidelity insists they're working hard on security--according to Gizmodo , they'll be generating a unique ID number for every single transaction, which should put minds at ease.
No word on exact release date or price yet.