http://xamarin.com

Xamarin is the new standard for enterprise mobile development. Their platform enables businesses to reach all major device platforms - iOS, Android, Mac and Windows - with 100% fully native apps from a single code base.  With Xamarin, enterprises standardize mobile app development in C#, share on average 75% source code across platforms, and leverage their existing skills, teams, tools and code to deliver great apps with broad reach quickly.  Xamarin is used by over 450,000 developers and over 17,000 paying customers, including Microsoft, Kimberly-Clark, Clear Channel, Schindler, McKesson, Halliburton, Cognizant, GitHub, Rdio and WebMD, to accelerate the creation of mission-critical consumer and enterprise apps.