Possible Duplicate:
Rails 3 deprecated methods and APIs
What resources are out there (free or paid) that help walk you through the process of migrating a Ruby on Rails 2 application to Rails 3? I've seen some blog posts (some of which seem out of date) and an eBook for sale somewhere on the RoR website, but what can you recommend as an accurate and complete explanation of what changed from version 2 to version 3 and what needs to be updated when porting to a Rails 3 environment?