UPDATE: During their earnings call earlier this week, Starbucks announced that over 3 million payments were received via mobile phones. That makes Starbucks the largest mobile payments system in the world…

Starbucks recent announcement of an iPhone app that can be used to pay at the register has received a lot of press this week. As did McDonald’s announcement in the UK of its contactless card payment system. From a technology standpoint, this app is one of a number of new systems that have recently come into the market – we discuss some of the other options available to retailers here. We’ll keep our readers updated as to which systems gain traction following in-market testing.