OpenIdAuthentication is depend on gem ruby-openid 1.1.4. In addition, ruby-openid 1.1.4 is broken with 1.0.1 gem :(
So, I applied patch(Ticket#10604) and they works well.

1. Install gem ruby-openid(2.0.4)

      1  gem install ruby-openid
   

2. Install plugin

      1  $ ./script/plugin install http://svn.rubyonrails.org/rails/plugins/open_id_authentication/
   

3. Apply patch

   • Get a patch and save as ticket10604.diff
     http://dev.rubyonrails.org/ticket/10604

   • Move diff file to plugin root

        1   #{RAILS_ROOT}/vendor/plugins/open_id_authentication/ticket10604.diff
     

   • Move to plugin root and do patch command

        1  $ patch -p1 < ticket10604.diff
        2  patching file init.rb
        3  Hunk #1 FAILED at 1.
        4  1 out of 1 hunk FAILED -- saving rejects to file init.rb.rej
        5  patching file lib/generators/open_id_authentication_tables/open_id_authentication_tables_generator.rb
        6  patching file lib/generators/open_id_authentication_tables/templates/migration.rb
        7  patching file lib/open_id_authentication.rb
        8  Hunk #5 succeeded at 69 with fuzz 1 (offset -2 lines).
        9  Hunk #6 succeeded at 88 (offset -2 lines).
       10  Hunk #7 succeeded at 152 (offset -2 lines).
       11  patching file lib/open_id_authentication/association.rb
       12  patching file lib/open_id_authentication/db_store.rb
       13  patching file lib/open_id_authentication/nonce.rb
       14  patching file lib/open_id_authentication/setting.rb
       15  patching file tasks/open_id_authentication_tasks.rake
       16  patching file test/normalize_test.rb
       17  patching file test/open_id_authentication_test.rb
       18  patching file test/status_test.rb
     

4. Do some work in README

   • Creating tables

        1   rake open_id_authentication:db:create 
     

   • Add some routes

        1  #config/routes.rb
        2    map.open_id_complete 'session', :controller => "sessions", :action => "create", :requirements => { :method => :get }
        3    map.resource :session
     

   • Generate SessionsController, and create vews/sessions/new.html.erb
     Tip:NOT to use sample code in agilewebdevelopment.com. Use sample code in README.

        1      def open_id_authentication
        2        authenticate_with_open_id do |result, identity_url|
        3          if result.successful? && @current_user = @account.users.find_by_identity_url(identity_url)
        4            successful_login
        5          else
        6            failed_login(result.message || "Sorry, no user by that identity URL exists (#{identity_url})")
        7          end
        8        end
        9      end
     

5. Ommit version of ruby-openid

      1  #open_id_authentication/init.rb
      2  begin
      3  #  gem 'ruby-openid', '=1.1.4'
      4    gem 'ruby-openid'