Last year Visa and MasterCard settled a legal dispute with a group of merchants claiming collusion on the part of credit card issuers in fixing swipe fees, the amount the credit card companies charge a merchant for each transaction.

FORBES: New Credit Card Swipe Fee Rules Are Good News For Shoppers

This app will give the retailers an upper edge to get better swipe fees from the credit card networks.

FORBES: Wal-Mart And Friends Plan Mobile-Payments Network To Fight High Card Fees

Probably the most useful feature is the ability for a passenger to swipe their credit card on the machine to pay for the fare: that's right, no more fumbling in your pocket for change.

ENGADGET: Digital Dispatch's TLC SmartCab GPS taxi solution