app.yml

# Rails Config.
# Copyrighted(c) Douglas F Shearer 2009
# Licensed under The MIT License.
# http://douglasfshearer.com/blog/simple-rails-config
site:
  url: http://example.com

authentication:
  username: bob@example.com
  password: myhackproofpassword

flickr:
  api_key: d3c3576398a4876c920553b714bc177f
  username: flickrusername

# Akismet.
wordpress:
  api_key: 876c920553b7

config.rb

# Rails Config Loader.
# Copyrighted(c) Douglas F Shearer 2009
# Licensed under The MIT License.
# http://douglasfshearer.com/blog/simple-rails-config
module Config
  
  class ConfigStore
  
    # Takes a hash as an argument.
    # If this hash contains other hashes, these too will turned into
    # ConfigStore objects.
    def initialize(contents)
      @contents = contents
    
      @contents.each do |k, v|
        if v.is_a?(Hash)
          @contents[k] = self.class.new(v)
        end
      end
    
    end
  
    def method_missing(sym, *args)    
      @contents[sym.to_s] || super
    end
  
  end

  def config
    @@config ||= ConfigStore.new(YAML.load_file("#{RAILS_ROOT}/config/app.yml"))
  end
end

include Config

Usage

  >> config.authentication.username
  => "bob@example.com@"
  >> config.authentication.password
  => "myhackproofpassword"