Blackberry-maker RIM is the undisputed smartphone leader in the US, according to the latest data from comScore’s mobiLens survey, which tracks key trends in the US mobile phone industry.

For the 3-month average period ending May 2010, RIM enjoyed a 41.7 per cent market share, with Apple in second place on 24.4 per cent, Microsoft in third on 13.2 per cent, and Android fourth on 13 per cent. comScore notes the stats do not include sales of the iPhone 4, which went on sale at the end of May.

Samsung is the top handset manufacturer overall, with a market share of 22.4 per cent, followed by LG on 21.5 per cent, Motorola on 21.2 per cent, RIM on 8.7 per cent, and Nokia on 8.1 per cent.

For the 3 month period to the end of May, 234m Americans aged 13 and older used mobile devices, and 49.1m people owned smartphones, an increase of 8.1 per cent over the previous quarter.

The mobiLens stats also throw light on US mobile subscribers activity on their mobile phones. During the three months to the end of May, 65.2 per cent of US mobile subscribers used text messaging on their mobile device, up 1.4 percentage points over the previous quarter. Browsers were used by 31.9 per cent of U.S. mobile subscribers, an increase of 2.3 percentage points.

30 per cent of subscribers used downloaded applications, an increase of 2.1 percentage points over the previous period. The number of people accessing social networking sites or blogs on their mobile also grew by 2.6 percentage points to 20.8 per cent of mobile subscribers.