Google\'s Sketchup is a nice, simple 3D-object modeler. Moreover Google has an enormous warehouse of 3D objects so that you actually don\'t have to do much modeling yourself if
The answer depends on what you want to do exactly. If you just want to see the image you could export as an .obj file (tessellation file, not object code!).
Try this for example:
bunny = Import["http://graphics.stanford.edu/~mdfisher/Data/Meshes/bunny.obj", "OBJ"]
If you actually want to work with it as a solid model you're going to have a more difficult time. Solid models have fairly complex data structures to represent the topology as well as the geometry. You might be able to get the surfaces out of the model for example, but you'll have to have some topology to say what portion of the surface is used by a face.