There are a few internet based programs that allow you to create floor plans and plan your home design. We previously spoke about Room Planner which was nice for furniture placement and decorating. Floorplanner takes it a little further and lets you move walls, create walls and completely create new floor plans.
It’s actually pretty solid and aside from structural design, it can handle basic tasks like the aforementioned furniture placement.
If you are building a home, redesigning, renovating, etc., give the free Floorplanner a try.