The proliferation of mobile payment systems to the general public has now made buying a daily cup of coffee as simple as using an iPhone app.

Starbucks, one of the largest coffee shop chains in the U.S., announced its launching a mobile payment system in all of its American stores. This will allow customers to pay for in-store purchases on various smartphones including Research In Motion's Blackberry and Apple's iPhone with the Starbucks Card mobile app.

The mobile app is an electronic version of a user's Starbucks card. It has a barcode, which can be scanned by a Starbucks employee on the counter top. The app allows customers to manage their Starbucks account, check their balance and reload it with a credit card.

Today, one in five Starbucks transactions is made using a Starbucks Card and mobile payment will extend the way our customers experience and use their Starbucks Card, Brady Brewer, vice president Starbucks Card and Brand Loyalty, said in a statement. With mobile payment, the Starbucks Card platform further elevates the customer experience by delivering convenience, rewarding loyalty and continuing to build an emotional connection with our customers.

Starbucks has already tested this mobile payment system in Northern California, New York and more than 1,000 Starbucks in U.S. Target stores. The company says customers put more than $1.5 billion on Starbucks Cards in 2010, a 21 percent increase from 2009. With the mobile app, it expects even more in 2011.

Mobile payment is just one example of how we're continually innovating on behalf of our customers to enhance the Starbucks Experience, Brewer said. A growing segment of our customers use smartphones, and through the Starbucks Card Mobile App, we're providing them with the fastest way to pay.