Google Sketchup Resources
Download - http://www.sketchup.com/intl/en/download/index.html
Tutorials - http://www.sketchup.com/intl/en/training/videos.html
Official Teacher Resource - https://sites.google.com/site/sketchupprok12statewidegrant/class-files
Good Overview
Google Sketchup for Educators
http://sitescontent.google.com/google-sketchup-for-educators/Home
Tip and tricks and a good Student Showcase
Using Goolge Sketchup in the Classroom
Long but worth it! (58 minutes)
Creating a 3D classroom
http://www.youtube.com/playlist?p=PL95E778E89AC951C4&feature=mh_lolz
These 7 short videos below walk you through how to setup and create your 3D classroom using the Google SketchUp program.
2D and 3D geometries
http://mathforum.org/sketchup/videos.html
There are many relationships between three of the Platonic solids: cube, tetrahedron, octahedron. This video highlights one of these relationships: starting wtih a cube, you can generate tetrahedrons, then uncover an octahedron. All by using a few simple SketchUp tools .
Suggested Projects for your classroom
http://www.3dvinci.net/teacherguide/teacherguide.pdf