Softbank customers in Japan can simply get an NFC sticker to add some contact-less payments to their iPhone 4, but most folks don't have it quite so easy just yet. There are some alternatives while you wait for Apple to hop on the NFC bandwagon, however, like this solution from Unplggd's Vivian Kim. It uses one of the smaller NFC-equipped credit cards now available from some banks, which is apparently just small enough to fit under the back cover of an iPhone 4 (a clear one, in this case, to show off your cleverness). And, yes, it apparently still works just fine under there -- even if you add a case on top of it.