Now that would be great news. With WP8 devices running ARM and WinRT supporting ARM aside from the screen size and "phone" related features why wouldn't WP8 have the same (albeit limited) API? I'm just asking as I'm not a WP8 developer but am always looking why we should support WP8 in addition to Android.
I think the big reason is due to the screen sizes, to be honest. However, that's entirely about the UI portions of the APIs. Everything else should be the same. This includes the APIs for talking to the various sensors, the WinRT contracts, etc. I was a bit disappointed when we found out the WP8 APIs were little more than a revision of the WP7 APIs.