We’ve taken another step toward your iPhone becoming your wallet and cash register on launch of an iPhone (and iPod touch)-based payment system.The system has been introduced by Twitter co-founder, Jack Dorsey, and launched a website for its services this month (December).It lets people authorize, accept, and process credit card payments through their mobile devices using an inexpensive dongle/accessory. Transaction details aren’t stored on the iPhone itself, it’s just used as