• by Mark Walsh  @markfwal, May 6, 2011

Android's share of the U.S. smartphone market reached 34.7% for the three months ending in March, up six percentage points from the prior three-month period, according to comScore. The share of the Google mobile platform was also up from 33% in February.

Most of the Android gain came at the expense of BlackBerry-maker Research in Motion, whose market share fell 4.5 points in the first quarter to 27.1%. Apple's iOS smartphone operating system was third, at 25.5%, up just 0.5%.

Rounding out the top five were Microsoft's Windows Mobile/Windows Phone 7 platforms, with 7.5%, and Palm's webOS, with 2.8%. Both were down 0.9% from the fourth quarter. Microsoft still has yet to see its market share move into positive territory after launching the WP 7 operating system last fall.

The new comScore report also showed mobile data usage continues to grow, albeit incrementally. In that vein, the proportion of U.S. wireless users who browsed the Web increased about 2 points to 38.6% in the first quarter.

The share using downloaded apps grew 3% to 37.3% and the proportion of people social networking on phones increased 2.6% to 27.3%. More than one-quarter played mobile games and 18% listened to music on mobile devices, with both activities -- up 2.5 and 2.2 points, respectively.

When it comes to manufacturers, the market share of category leader Samsung was virtually unchanged from the prior quarter, at 24.5%. The same goes for No. 2 U.S device maker, which remained at 21% share. Motorola slipped a bit to 15.8% from 16.7%, while RIM was flat at 8.4%, and Apple's share increased a point to 7.9%, with a likely boost from the release of the Verizon iPhone.

Recent data from technology research firm IDC showed the mobile phone market worldwide grew 20% in the first quarter from a year ago, while the smartphone market surged 80%. Apple ranks as the No. 4 handset maker globally, with a 5% share of the industry.