Android has already assumed its position on top of the global smartphone totem pole, and now, according to two separate analytics firm, it has seized the top spot in the United States as well. In separate reports filed this week, both comScore and Nielsen agree, the little green alien reigns supreme Stateside. comScore gives Android 31.2% of U.S. market share, followed by Research In Motion with 30.4% and Apple with 24.7%. Nielsen reports similar number, with Android claiming 29% of the pie with Research In Motion and Apple each sharing 27%. All hail your new mobile operating system overlord, Android!