• by Mark Walsh  @markfwal, February 15, 2012

Apple became the world's top smartphone seller in the fourth quarter, with a 23.8% market share, and for 2011 overall, with a 19% share, according to new data released Wednesday by Gartner.

Worldwide smartphone sales to end-users increased to 149 million units in the quarter, a 47.3% jump from a year ago. Total smartphone sales in 2011 reached 472 million units and accounted for 31% of all mobile devices sales, up 58% from 2010.

In the smartphone OS market, Android’s share declined slightly from the prior quarter to 50.9% as a result of strong iPhone sales driven by the iPhone 4S, and the weakness of key Android manufacturers in emerging markets. The market share for Apple’s iOS grew 8 percentage points from a year ago to 23.8%, but analysts expect its share to drop again in the next two quarters as demand for the iPhone 4S slows.

Microsoft’s OS share fell to 1.9% as the worldwide rollout of Nokia’s first Windows Phone devices, the Lumia 710 and 800, didn’t begin until late last year and had little impact on fourth quarter or 2011 sales.