US : Despite the popularity of the iPhone and the general touch-screen mania that has swept the U.S. over the past year, few people actually watch video on their cell phones. But the numbers are on the rise, according to a new report issued by the Nielsen Co.

According to Nielsen, 10.3 million U.S. mobile subscribers access video content on their phones during a given month -- roughly 5 percent of all wireless subscribers.

However, the audience is growing -- up 14 percent in 2008 vs. '07 -- driven primarily by the presence of more Internet-friendly phones in the market. (Back in 2005, a report issued by mobile researcher M:Metrics found that just 1 percent of mobile users watched video on their phones.)

Nearly two-thirds of viewers are watching video via the mobile Web (66 percent), though paid subscription services and purchased downloads continue to account for a sizable amount of viewership.

Not surprisingly, iPhone users skew high when it comes to video. More than a third of iPhone users claim to regularly watch video. And as of Q3 of 2008, 11 percent of all users who streamed mobile video did so using an iPhone, according to the report.

Not surprisingly, the top Web destination for consuming mobile video is YouTube -- likely do in part to the site’s prominent anchor position on the home screen of all new iPhones. Nielsen found that in Q3 '08, roughly three million unique users accessed YouTube via their mobile devices.