There are some excellent websites that have a wealth of information on preparing  rooms for painting, which paint to choose, faux finishes and more.  Check out Benjamin Moore who has a system called Personal Colour Viewer.  You can choose your room, change the colour fan to your choice and 'paint' walls, trim, ceilings, etc.

And Ralph Laren Home has a fantastic website as well, that should answer all your colour questions. Again you can choose a room, choose a color and watch the room change.

These sites also include a paint calculator, a Personal Portfolio, color choices identified with the product number and you can e-mail the images and details to your painter!