Twitter founder Jack Dorsey obviously has a fertile mind where useful solutions to everyday problems are born. His latest idea is already a $40 million start-up company called Square that provides the hardware and software to turn your smartphone into a credit card processing terminal anywhere you can get an internet signal. Right now available for the iPhone with an Android version coming soon (Square is looking for an Android client engineer), the app itself is $1 and the swipe accessory which attaches to your phone is given out for free. This is a service that can have practically unlimited potential and shows you how the rich get richer. In the meantime, TechCrunch has produced a short video showing how Square works.