Microsoft released today a file encryption program, called Microsoft Private Folder. The way it works is that it automatically creates you a folder and you can add files in it, which are encrypted as soon as you put them in.
The program is part of the Windows Genuine Advantage Offers, so you'll need to pass the Windows Genuine Advantage validation before installing. You'll need to set your location to United States using the scrollbar at the top of the page. Else, the offer won't be there.