Apple has released Bootcamp for Windows 32-bit and 64-bit (or through Software Update). The release was originally timed to be at the end of last year and supports Microsoft Windows 7 Home Premium, Professional, and Ultimate.
Remember, Apple only supports Windows 7 on some Intel machines. To see if you are one of the lucky ones, check here.
To upgrade from Vista, you'll also need the update utility which unmounts the disk and updates it for Win
