Some links, for my reference as well as yours:
SketchUp Free download (PC only, Mac “soon”)
SketchUp Pro Google Earth plugin (April 26)
SketchUp Google Group (aimed at SketchUp Free users)
Google 3D Warehouse:
SketchUp Help Center (getting started)
SketchUp User’s Guide (thorough)
Video Tutorials (SketchUp, 3D Warehouse, Google Earth)
SketchUp Quick Reference Card
The 3D Warehouse network link pinpoints the locations of the geolocated warehouse items in your view. Click on the icon, and the popup window will let you download the 3D KML model directly within Google Earth (innovation!).
Mac users can of course view 3D KML models now, even if SketchUp Free isn’t quite ready yet for the Mac. However, I could only get direct downloading to work on my Mac using the newest point release of Google Earth Mac from a few days ago. So if you don’t already have version 3.1.0621.0 (beta), go get it.