The official SketchUp homepage where you can download both versions of the software, link to other training resources, and much more.
The official spot for SketchUp support; if there's something you need to know, this is a good place to start looking for the answer.
A huge online community of SketchUp users who share ideas, solutions and other information.
The unofficial home of the SketchUp faithful. You won't find a more international, dedicated and enthusiastic group of SketchUppers anywhere else on the Web.