<script>         
         jQuery(function(){         
         $("#banners img").hover(function(){         
         $(this).stop().animate({opacity:'1.0'})},         
         function(){$(this).stop().animate({opacity:'.3'} )}         
         );         
         });         
         </script>         
         <style>         
         #banners img{opacity:.3;filter:alpha(opacity=30)}         
         </style>         
         <div id="banners">         
Ваши баннеры        
         </div>