Microsoft has begun selling ads on its U.S. MSN mobile page, according to a Reuters report.

Microsoft, which already sells mobile ads abroad, will begin its U.S. mobile push with ads for Bank of America, Paramount Pictures and Jaguar.

So far, mobile has yet to rival computer-based web advertising, however, that hasn't stopped Microsoft and its competitors from betting big on the space. While Google continues to press for an open network, Yahoo! has been working hard to lock up carriers and handset manufacturers.