#controller  

def test
    @items = Todo.find(:all, :order => "pos")
  end

  def update_positions
    i = 1
    params[:sortable_list].each do |item_id|
      @item = Todo.find(item_id)
      @item.pos = i
      @item.save
      i += 1
    end

    @test = Todo.find(:all, :order => "pos")
    render :layout => false, :action => :test
  end

#view
<html>
<head>
<%= javascript_include_tag 'prototype','controls','effects','dragdrop'  %>
</head>
<body>

<div id="items">
<ul id="sortable_list">
<% @items.each do |item| %>
<li id="item_<%= item.id %>"><span class="draghandle"><%= item.description %></span></li>
<% end %>
</ul>
</div>

<%= sortable_element('sortable_list', :update => :sortable_list, :url => {:action => :update_positions}) %>

</body>
</html>