InitializeMenu = function()
{
  $$('#navigation li').each( function(el) {
    
    el.onmouseover = function()
    {
      el.addClassName('over');
      ul = el.down('ul');

      if (ul) ul.setStyle({ display: 'block' });
      
    }
    el.onmouseout =  function()
    {
      el.removeClassName('over');
      ul = el.down('ul');

      if (ul) ul.setStyle({ display: 'none' });
      
    }
      
  });
}
Event.observe(window, 'load', InitializeMenu );