Coffee shop chain Starbucks this week brought the power of mobile payments via cellphone to new users — provided those customers happen to have the right kind of device. The company announced that customers at its retail outlets in the United States will be able to pay for purchases using its mobile payment app on select smartphones. This covers all nearly 6,800 of the company’s stores and the more than 1,000 Starbucks outlets in Target department stores. The free Starbucks Card Mobile App runs on iPhones, iPod touches, and select BlackBerry smartphones, Starbucks said.