Google Sketchup lets you create 3-D models of anything. You can build models from scratch, or you can download what you need. People all over the world share what they’ve made on the Google 3D Warehouse. Dozens of video tutorials, an extensive Help Center and a worldwide user community mean that anyone who wants to make 3D models with SketchUp, can do so – free.
You can learn more at the Google Sketchup blog, and check out the second Google Model Your Town Competition. Model Your Town is about geo-modeling – making photo-textured models of real-life buildings that appear in Google Earth. The Model Your Town Competition is also a chance to celebrate your town by adding it to the 3D map.