Event.observe(window, 'load', function() {    
    $$('#main .item').each(function(e) {
      Event.observe(e, 'mouseover', function() {
        Element.addClassName(e, 'hover');
      });  
    
      Event.observe(e, 'mouseout', function() {  
        Element.removeClassName(e, 'hover');  
      });  
    });
});