The ShopKeep iPad app is a point-of-sale iPad app that, according to its website, allows retailers to "ring up customers, print paper receipts, pop the cash drawer, take credit cards, manage inventory, update pricing and have real time access to sales numbers through the web."
It's great for saving space on the sales floor, and it eliminates the need for bulky terminals. Additionally, it saves all purchase history in the cloud. This means you would be able to access live data like reporting, sales figures, etc. from anywhere. It also heralds more inroads to mobile devices for salespeople. The UI is touch based, and seemingly quite intuitive. It also caches sales, so you can still conduct business even if your internet connection is down.
Check out the video demo below. I was really impressed with how quickly the peripherals responded to the touch commands.
A possible issue might be the fact that the data is stored on the company's server. Shop keepers may worry about security and would have to be educated. Additionally, this seems to be tooled for smaller outfits with small amounts of inventory. It's probably not the best solution for bigger business. Still, it's a great example of mobile/touch devices making their way into the retail world.
And for consumers, it means they can check out anywhere in the store, just like at Apple stores.