http://github.com/ccjr/translated_attributes

gistfile1.rb

# Migration
create_table "posts" do |t|
  t.string "title_ar"
  t.string "title_en"
  t.text   "body_en"
  t.text   "body_ar"
end

# Model
class Post < ActiveRecord::Base
  translated_attributes :title, :body
end

# View/Controller
@post = Post.first
I18n.locale = 'en'
@post.title #=> post.title_en
I18n.locale = 'ar'
@post.title #=> post.title_ar