Google has launched a free 3D modelling software called SketchUp that lets you quickly create 3D models - a la dummies version of 3D Studio Max. As with most software coming out of Google stables SketchUp is also delightfully simple to use. There's a free and a pro version (that comes for a price) with one major difference being that only the pro version lets you export models into different file formats. The free version lets you save either in the native SketchUp format or in a format that's suitable for use with Google Earth. While the download is a tad heavy at 19MB it is certainly worth it. The downside is of course that they don't let you save the models in any real format that you can use (in an OpenGL program for instance). SketchUp is another Google acquisition incidentally.