Officially, Microsoft won’t reveal its strategy for Windows Phone 7 developers until the Mix conference in March. Unofficially, it looks like Silverlight, XNA, and .Net will play key roles.
A source tells ZDNet: “The dev platform is Silverlight 3, plus elements of 4, using Blend and a Visual Studio add-in. The kicker is that while it is XAML-like, it is not pure XAML (Extensible Application Markup Language). This is actually OK, as it keeps the footprint nice and small. In theory you can make an entire app inside of Blend, but I think you will need Visual Studio to hook it all together in C#. In the war vs. Apple for apps, every .Net developer just became a Phone developer.”