Today at Building Windows 8 blog, Microsoft detailed the portrait mode support in Windows 8. So far most of the time we have seen Windows 8 in action only in landscape mode , but it also supports portrait mode very well.
Windows is also designed to work great in portrait mode. We studied extensively scenarios like reading news in the web browser, looking at portrait photos, and scrolling through long lists of email messages, and we folded what we learned into designing a system that works seamlessly across orientations. We tuned the system experiences like the keyboard, file picker, and charms to work great in portrait as well as landscape. We wanted to make it so you don’t need to relearn the system when you switch to portrait mode; it just works.
As usual, needless to say its a long blog post with lots of stuff to read.
Find it here.