A few links that caught my eye today:
An introduction to Ruby on Rails for DB2 developers - Nice article if you’re a DB2 user and want to know what the fuss is about. Written by Edd Dumbill.
Sapphire in Steel: The Little Book of Ruby - Nice introduction to Ruby with plenty of code samples, in PDF form.
Ruby Cookbook - The Perl Cookbook, ported to Ruby.
Configuring Rails Environments - The Cheat Sheet - Now you can find out what all of those neat settings in config/environments/* are.