As we first reported over the summer, Twitter creator Jack Dorsey has a new project. Originally known as "Squirrel," the name has been changed to Square , but the idea remains the same: A hardware/software combination for mobile devices (launching first for the iPhone/iPod touch) that allows vendors to easily accept and process credit card payments. Our full post on Square is here . I had a chance to catch up with Dorsey today at the new Sightglass Coffee (which Dorsey is an investor in) in San Francisco. In the video below he talks a bit about the idea behind Square, and then we do a demo in which I actually buy mine and Dorsey's coffee at Sightglass (one of the merchant launch partners for Square). It's a bit hard to see the iPhone's screen due to the daylight, but you can easily see just how fast Square works for transactions. Simply put, it's amazing.