Worldwide: Android beats iOS slightly. http://gs.statcounter.com/#mobile_os-ww-monthly-201108-20120...
Europe: iOS beats Android slightly. http://gs.statcounter.com/#mobile_os-eu-monthly-201108-20120...
North America: iOS beats Android by 10% http://gs.statcounter.com/#mobile_os-na-monthly-201108-20120...
South America: Android beats iOS by 28% http://gs.statcounter.com/#mobile_os-sa-monthly-201108-20120...
Asia: Android beats iOS by 10% http://gs.statcounter.com/#mobile_os-as-monthly-201108-20120...