XamarinCreate Native iOS, Android, Mac and Windows apps in C#
Xamarin delivers high performance compiled code with full access to all the native APIs so you can create native apps with device-specific experiences. Anything you can do in Objective-C or Java, you can do in C# with Xamarin.
MvvmCross for XamarinThis project provides a cross-platform mvvm mobile development framework built on top of:
Silverlight for WP7, WP8
Mono for Android (or Xamarin.Android)
MonoTouch for iOS (or Xamarin.iOS)
the WinRT XAML framework for Windows 8 Store apps.
Mono for Mac (or Xamarin.Mac)
This project makes extensive use of Portable Class Libraries to provide maintainable cross platform C# native applications.