Google SketchUp is the finest (and most innovative) tool available for anyone designing anything from coffee pots to skyscrapers. You can create 3D modelling easily with it.

Redecorate your living room. Design a new piece of furniture. Model your city for Google Earth. There’s no limit to what you can create with SketchUp. There are also dozens of video tutorials, an extensive Help Center and a worldwide user community mean that anyone who wants to make 3D models with Google SketchUp, can.

Requirements: -
Demo: http://sketchup.google.com/
License: License Free