New Tablet PC App from Microsoft Research: InkSeine

• You can blaze a super-fast trail by using radial menus for pen commands. Just hover over a menu to preview the commands. Touch down in the center of the menu and drag towards the command you want to activate.
• You can select existing ink right on the page to initiate a search.
• Create queries in the context of your notes to keep track of searches, reuse them, or return to them later.
• Easily find emails, documents, ink notes, or web pages without leaving your notes.
• Drag links to the documents and web pages you find right into your notebook or drag images into your notes, from search results or file folders.
• Filter your desktop searches by file type or date with simple pen controls.
• Use powerful gestures throughout the application.
• Create automatic hyperlinks from your notes and screen captures.
• View your notes page-by-page, like a real notebook. 
• Pages scale to fit the screen when you rotate your tablet.
• Much, much more

Of course, Microsoft Research has tutorials, Help documentation, forums, videos, and a blog  up and running, just in case the app is not totally and unequivocally user-firendly.