At Architect Studio 3D you can design a house with some tips from Mr. Wright. It starts by picking your "client", whose needs you will attempt to meet when designing (or you can just ignore them and go hog wild building your dream house). From there you get to choose location, design the exterior, landscape, and design the interior, from the walls to the leather chair in the reading nook.
To be honest, the selection of materials isn't what it could be, but for a free program it's well developed. You can change from floor plan view to a 3D view that allows you to move through the house, changing your view, using your mouse. When you're done, you can tour your house and add it to the "Design Gallery".