The long anticipated Silverlight control for Virtual Earth took a step closer yesterday with the release of a very mature CTP. The experience is nearly identical to the old HTML map (which they call the AJAX map), but with the smoothness of Silverlight's DeepZoom. They also have an interactive SDK, just like the old one, with clear migration hints.
The really exciting thing about it is the fact that you can render any aribtrary Silverlight XAML on top of the map. This opens up Google Earth quality content in a browser, which raises the stakes yet again in the GIS war. Add this to the location awareness zeitgeist and we have some interesting times ahead.
I'm still confused about how they plan to maintain both the Silverlight and VE3D platforms. Is the goal ultimately a single platform? Given that one is based on managed DirectX and one is based on the Silverlight XAML subset (which doesn't do 3D), I can see no technical middle ground. Perhaps they will harmonize the SDK's to make it easy to write for both, but not knowing which to bet on makes me uncomfortable.
Interactive SDK (you probably need to register with Microsoft Connect)
Chris Pendleton @ MIX with the nerds wot wrote it. Some nice examples of the free-form XAML layering.