A Ruby gem to manage ISO 3166 country names and their
corresponding alpha-2 and alpha-3 codes. Additional
support has been added for ISO 4127 currency information
and standard  conventions for states in the USA
(based on the 3166-2:US code).

ISO 3166 country codes reference:
  http://en.wikipedia.org/wiki/ISO_3166-1

ISO 4217 currency information:
  http://www.xe.com/iso4217.php
  http://www.xe.com/symbols.php

ISO 3166-2:US code reference:
  http://code.google.com/apis/chart/statecodes.html
  http://en.wikipedia.org/wiki/ISO_3166-2:US

ISO 639 language reference:
  http://en.wikipedia.org/wiki/List_of_ISO_639-1_codes