Google SketchUp is software that you can use to create 3D models of anything you like. The main page (including the download) is at http://sketchup.google.com/. It’s free so you can try it at home too! You can build models from scratch, or you can download what you need. People all over the world share what they've made on the Google 3D Warehouse. It's a huge, searchable repository of models, and it's free. Explore the Google 3D Warehouse at http://sketchup.google.com/3dwarehouse/.
Self-Paced Tutorials
Self-paced tutorials are SketchUp files designed to give interactive training to help you develop your SketchUp skills.
2. Google SketchUp Self-Paced Tutorial - Part 1
3. Google SketchUp Self-Paced Tutorial - Part 2
4. Google SketchUp Self-Paced Tutorial - Part 3
Our Class Assignments
Sketchup Design Exercise 1, Google Design Exercise 2, Sketchup Design Exercise 3, SketchUp Daily Exercise 4
SketchUp Rubiks Cube Jenga Setting Up A Minecraft Model Building A Minecraft House
Final Sketchup Assignment and Rubric
Sketchup Bonus Project 1 , Bonus Project 2 , Bonus Project 3 , Bonus Project 4 , Bonus Project 5
Bonus Projects
Other Sketchup Resources
Google Sketchup Toolbar Glossary
Video Tutorials
Google has a number of video tutorials available at http://sketchup.google.com/training/videos.html. To view a tutorial, select one from the list and press Play (or simply click the video). To view the tutorials full screen, click the full screen button 
at the bottom of the video.
Are the videos blocked?
Try here instead.
Getting Started with SketchUp Videos