MonoGame replaces it and is available now for Windows 8. In fact I've completed two games using MonoGame which run using 95% the same code on Windows XP, Vista, 7, and 8. Pretty soon there will be a Linux and Android version as well.
If you want to see what's possible you can check them out:
I was looking for an 'official MS technology' replacing it. I know monogame. I wouldn't think anyone NEW to game dev would start with it; it's for XNA devs wanting a life after, right?
If you want to see what's possible you can check them out:
1) Adlib: http://apps.microsoft.com/webpdp/en-US/app/adlib/9cc0809e-b0...
2) Petunk http://apps.microsoft.com/webpdp/en-US/app/petunk/c03ecbca-4...
You can also read a great deal more about the process as well as watch me convert a game live here: http://www.reddit.com/r/windows8/comments/10g4r2/check_out_m...