Google 3D Warehouse
Photoshop CS3 Extended's new 3D capabilities make it easy to modify models created in other 3D programs. However, there are some that may not have a 3D modeling program. Google has introduced the Google 3D Warehouse, which is a library of free 3D models you can import directly into Photoshop and manipulate using the available 3D tools. Here is the site: http://sketchup.google.com/3dwarehouse.