Recently my wife took a stall at a Sunday market to clear some of the excess stock from her store.
In order to accept cards she needed to use an old school credit card machine.
Pretty soon she'll be able to accept payments via her iPhone.
Jack Dorsey one of the founders of Twitter has created mobile payment service Square.
Simply download the Square app from the iTunes Store.
Once you've done that they send you a small swipe reader that you plug into your iPad and soon iPhone.
Then you're pretty much ready to go. Easy!