They've only said "minimal code changes", "two days of work"; also only mentioned native code in the context of games and nothing to suggest support for HTML/JS-based apps (which would imply WinRT support). "Recompile + UI tweaks" would be a headline feature for the SDK, not stating such outright leads me to believe this isn't the case.
EDIT: just said that the CLR is now identical between phone and W8, but again "share more code", still not naming WinRT.
They said that native code is going to be supported. That tells me WinRT will be as well; it's not like people are going to be writing MFC apps for it.
Although they didn't come out and say this, the impression I get is they are bringing over the WinRT APIs for lower-level stuff like networking, etc., while the XAML UI stuff is an extension of the Silverlight in WP7x rather than a port or adaptation of Windows.UI.Xaml from Windows 8.
If that's what they're doing, I think it's the right decision - the UI conventions themselves are different between the phone and Windows 8 (more than people realize, despite having a similar visual aesthetic), so you'd have to rewrite much of the UI anyway - so why break compatibility with WP7.x.
EDIT: just said that the CLR is now identical between phone and W8, but again "share more code", still not naming WinRT.