One of the sad things about the move to the new Windows 8 Metro platform is the way that XNA seems to have been left by the wayside, with no way forward for the platform and no workable alternative from Microsoft. I see this as a bit of an own goal really, just when people like Sony are releasing a suite that makes it easy for C# developers to create and deploy applications, and when Microsoft are looking for a way to get developers on board with the Windows 8 way of doing things, they seem to have pulled the plug on the best way to do this.
However, it is not all bad news. The people at MonoGame are beavering away on a solution that will let you leverage your XNA experience and make games for Windows 8 Metro. Following the instructions in this blog post I managed to get a screen full of Cornflower Blue on my Windows 8 system. The familiar Update and Draw methods are present and correct, along with all the XNA types that you know and love. At the moment getting content (fonts, textures and sounds) into your game is a bit of a faff, in that you have to make a Visual Studio 2010 project and use that to prepare the content for use in your Metro program. Having said that, it does work and, thanks to the dedication of the Mono team it looks like we will have an XNA trajectory on Windows 8 Metro. It is just a shame that it is not coming from Microsoft.