Google has made a of version Sketchup called 'Google SketchUp' available for free! You can go here to learn more. You can also read this from the SketchUp guys about it.

Google has also announced the 3D Warehouse (a repository for 3D models).

And, you can read Google Earth Blog's first take on this development. You will see it is my belief we will soon get a new version of Google Earth.