How about right from the horse's mouth? Here's the CrappyC (err, CurrentC) support document -- which I found on the Internet (TechCrunch needs to thank me):
http://support.currentc.com/
"d.Paying with Your CurrentC Wallet Retail Locations
To pay with your CurrentC app you must:
1.Have downloaded and installed the CurrentC application
2.Have registered your account with CurrentC
3.Have added at least one payment account.
Once youve completed these three steps, you can start using your CurrentC app to purchase goods and services at any of our participating locations. To make a payment using your CurrentC app at a store, select the Pay with CurrentC option at the register (If there isnt an option available inform the cashier or checkout clerk that you would like to pay with CurrentC) then follow the steps below.
◾Open your CurrentC application
◾Enter your 4-digit passcode
◾Press the Pay button
◾Either scan the Secure Paycode that the cashier presents (default) or press the Show button at the bottom of your screen to allow the cashier to scan your Secure Paycode
◾Select the payment account that you would like to use
◾Press the Pay Now button"