Microsoft acquired Xamarin earlier this year. Last week at Build, they announced that Xarmin would be free and open source:
http://www.anandtech.com/show/10212/mic ... pen-source

This means anyone can finally write a cross platform mobile app for free using Visual Studio Community Edition...

Well, after upgrading and installing... etc... etc...

I created a blank project and it doesn't compile... I tried this a few months ago with the same result, so I am not sure why I expected something different... You would think that the "Blank App" template should compile "out of the box"?

You still have to maintain 5 separate user interfaces... and there is no support for Windows 7 or XP... I may revisit it in a few years... but for now it doesn't look like I will be doing any Xarmin cross platform development...