I picked up Ruby on Rails: Up and Running at the local Borders a few weeks back with the intent of forcing myself through a second book length tutorial on Rails. Reasons included: 
- Long ago I learned it always helps to learn things from multiple independent sources, so I wanted to see how someone like Bruce Tate approached Rails.
- I have the beta PDF of Agile Web Development with Rails, but it’s over 600 pages now and not quite as approachable as a 167 page book.
- I like short, deep, vertical dives into topics.
- I have two small children, a full time job, and the occasional weekend day of paintball, so being able to pick it up for only an hour or so a night and make it through a chapter or so is nice.
Overall I’m down to the second to last chapter on AJAX now and the online photo app has been pretty good for solidifying some of my rails understandings. Since the authors do assume a good portion of their readers aren’t familiar with TDD the unit testing chapter is pushed to the very last chapter of the book and they don’t do the tutorial TDD style. I went ahead and used autotest and tested my way through the whole thing.
Five chapters in, I understand better now how integration tests work, and especially how to start with scaffolding code and build it out to a nice looking application. I’m expecting the AJAX chapter to be enjoyable. Not nearly as comprehensive as Agile Web Development with Rails, but not a bad introduction.