gistfile1.rb

class WeblogController < ActionController::Base
  # will render weblog/index.html.erb
  # note for older versions it will be index.rhtml, but it's still erb
  def index
    # more code here
  end
end

class AuthorsController < ActionController::Base
  # will render authors.index.html.erb
  def index
    @authors = Author.find(:all)
  end
end

# in weblog/index.html.erb

<%= render_component :controller => "authors", :action => "index" %>

# refactoring

class WeblogController < ActionController::Base
  before_filter :find_authors

  # will render weblog/index.html.erb
  def index
    # more code here
  end
  
  private
  
  def find_authors
    @authors = Author.find(:all) # Since v2.2(I think) you can do Author.all
  end
  
end

# in weblog/index.html.erb

<%= render :partial => 'author', :collection => @authors  %> # to render authors/author for each record in @authors

# also in v2.3 above you can simply do

<%= render @authors %>