Xamarin is Microsoft’s most exciting acquisition since Skype and Acompli. (Okay, LinkedIn is pretty exciting, too.) Now you can create iOS and Android apps by using Microsoft’s C#/XAML stack and shared portable class libraries. Xamarin’s great framework used to be pretty pricey ($1,000/year license for VS integration), but now it’s free. In this MVA video, Christopher Harrison and Gerry O'Brien guide you through the basics of getting started and building mobile apps by using the free Visual Studio project templates.
If you’re interested in a certificate, the edX class, Introduction to Xamarin Forms, is worth the $25. Yours truly just finished it, and I happily sport it on my LinkedIn profile.