First of all, many thanks to the folks at AtLast Software and at Google for making SketchUp Pro available to educators at such an unbelievable price — it’s now free for instructors!
As I re-acquaint myself with the application and begin to gear up for making illustrations of the crawfish boats, I am finding that there is an amazing variety of educational materials. One is [Google’s own collection of videos](http://sketchup.google.com/training/videos.html), which are divided into sections for [new users](http://sketchup.google.com/training/videos/new_to_gsu.html), intermediate users, advanced users, et cetera. There’s even a video on [modeling a tractor](http://www.youtube.com/watch?v=P0Daz4N-WLA&feature=channel).
There is also something called [The SketchUp Show](http://atotheo.libsyn.com/), which has a variety of lessons — they are up to Show 56 at this writing.
There is also a [SketchUp Cookbook](http://www.amazon.com/gp/product/0596155115?ie=UTF8&tag=johnlaudun-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=0596155115) published O’Reilly — link is to Amazon. If you have O’Reilly’s Safari Online Book service, then you can find the cookbook [here](http://my.safaribooksonline.com/9780596157784).