May I bring your attention to this : http://comscore.com/Press_Events/Press_Releases/2010/4/comSc...

    Top Smartphone Platforms
    3 Month Avg. Ending Feb. 2010 vs. 3 Month Avg. Ending Nov. 2009
    Total U.S. Age 13+
    Source: comScore MobiLens
    Share (%) of Smartphone Subscribers

                Nov-09 Feb-10  Point Change
    RIM 	40.8% 	42.1% 	1.3
    Apple 	25.5% 	25.4% 	-0.1
    Microsoft 	19.1% 	15.1% 	-4.0
    Google 	3.8% 	9.0% 	5.2
    Palm 	7.2% 	5.4% 	-1.8