I haven't tried it, but I did hear a podcast that Miguel was on. You'll need to redo the UI as Moonlight isn't on Xamarin's radar right now. The reason is that the app wouldn't look like a native iOS app. From the podcast, it sounded like business was very good for Xamarin.

>I wonder if anybody has used the MonoTouch from Xamarin to port a Silverlight app to iOs? Any feedback would be greatly appreciated.