I was just interested in these books about the "latest" version of rails. Are they about Rails 3.0.9?
The Rails 3 Way - Published December 20, 2010, I doubt it includes the 3.0.9 release.
Ruby on Rails 3 Tutorial - Published on December 26, 2010, also doubt this book covers 3.0.9
Agile Web Development with Rails - March 31, 2011 - don't know about this one.
I am currently using Django Nonrel with mongodb with very good success for some client work. It's actually deployed to AWS not App Engine, but the code between the two is virtually identical. AWS was chosen for video processing requiremets. The tools and short cuts django provides like the automatically generated admin have made the project viable. I haven't seen the db-indexer project before, but looking forward to checking it out.