I haven't had too many issues with the engine on windows phone 7. The latest revision includes the necessary xna 4.0 changes needed to port the demos and debugview to windows phone 7. You just have to create the WP7 game library projects for the engine and
debugview and use them. You'll want to double the default velocity and position iteration settings to get similar stability as you'd expect running on the PC or XBox360, due to the phone's 30fps limitation.
I think there is one minor compiler error when building for windows phone 7 - something about an uninitialized Vector2 being sent to a method by reference - it's easy enough to fix.
Also, the content projects for xna 4.0 aren't quite committed to source control yet, but if you're just using the debugview, then all you need to do is add the sprite font that debugview uses to your game's content project.
If you're looking for silverlight windows phone 7 support, I don't think there is a debugview that works with the version of silverlight on the phone, but the core library should work. I think you have to create a "Windows Phone Class Library"
project. XNA projects need the "Windows Phone Game Library" project instead.