I recently received a Starbucks gift card and created an online Starbucks account which is accessible via the free Starbucks Mobile Card application for iPhone. I went to my local Starbucks and ordered a tall Pikes Peak roast for $1.50. Instead of paying by cash, credit card, or my Starbucks card, I opened the Starbucks Mobile Card application on the iPhone and clicked on "touch to pay." A barcode was displayed on my phone which I placed in front of a scanner at the register to make my purchase. The cost of the coffee was immediately deduced from my account and displayed on the iPhone screen. Simple and easy.
While some have raised security concerns with Starbuck's approach, specifically the static barcode that is used, credit cards have their own set of security issues which are arguably more significant. I welcome the opportunity to use my smartphone for additional point of sale purchases.