Read the original post by Simon Jackson at XNA UK User Group
While right now I should be working hard on releasing our Alphalabs.cc project Vequencer I’ve decided to take some time out and write out a summary of the blogosphere’s thoughts on the future of XNA.
These are the best that are out there, some hard facts, some harsh realities and some comforting parting thoughts.
Here’s my view
It's certainly unclear in the long term what will happen to XNA or any other MDX equivalent provided by Microsoft but at least for the Short to Mid term XNA is still a stable and viable platform. The support for Windows / XBOX and Windows Phone as it stands today will continue to go forward under MS's usual response of "Continued support".
In fact it has been clearly stated all current WP7 apps/games will run on WP8 which may indicate there will still be a chance to develop XNA games for WP8, however that is done (reading between the lines would that also mean there would be a way to code XNA in Metro, personally I do not see a problem providing a managed layer on top of the C++ infrastructure today)