Microsoft has announced that Windows 8 and Windows Phone 8 will share most of the development experience. Just a tweak or two and your apps run on the other platform.
But what are the details? You could describe porting .NET WPF apps to Metro-style with the words "a tweak or two", but we know those tweaks can sometimes be huge.
Let's start out with porting a Metro-style Windows 8 app to Windows Phone 8 (which is my personal angle). What does that involve? Does it take advantage of the work we put into creating Snap views in some way, or are we targeting another form factor or framework?