I work a lot with Google SketchUp, I think that is a fantastic program, we can have a very realistic idea of a project that you want to do, is very simple and easy to use, I will leave an example of projection of my room, and what I want to do in it

In this case it was a great help. Because I want to remodel my room, so I have an idea of how it will stay, also did my whole house, it was much more harder to make it, but it was spectacular!

I fell better using AutoCAD, even if it isn't very suitable to make a draft.

Some totorials

http://br.youtube.com/watch?v=lTycE25eV4c -->making a home

http://br.youtube.com/watch?v=ZiMA1IAn8HU&feature=related --> sections