According to a study by The Nielsen Company 9 million mobile phone users in America have used their mobile phones to pay for goods and services and half of all data users say they expect to participate in mobile commerce in the future.

The study says that as of Q1 2008 3.6% of US mobile users paid for good with their phone. Men are more likely than women to use their phones for commerce and adults 25-34 are the most likely to use their phone for buying goods.

"As with other forms of electronic commerce, US consumers need proof that mobile transactions will be a safe, affordable and efficient complement to other modes of shopping," said Covey. "As long as retailers continue to meet those expectations, more consumers will come to view mobile shopping as a compelling and viable option."

Via Nielsen