Starting with Vista, Microsoft bundles support for ICC color profile calibration with the "Windows Color System." Even though Vista doesn't include a tool to create ICC profiles and the tool in Windows 7 is very basic, you can load any profiles that you generate by other means.
If you use the advanced display calibration wizard in OS X, it will generate ICC profiles for you. If you save the profiles for "all users" they will be stored in a central location. Then you can load and use them in Windows because Boot Camp 3.0 provides HFS+ drivers to mount the OS X system volume.
After you do the calibration in OS X, restart inot Windows. The calibrated ICC files should be readable on your "Macintosh HD" volume. On my machine they are in E:\Library\ColorSync\Profiles\Displays.
Right-click on the .icc files and choose "Install Profile". Then you can use Control Panel > Display > Ajust resolution > Advanced Settings > Color Managment to load the appropriate ICC profiles for each monitor. You can use the Advanced tab to set the default color profile per display for all users.