window.addEvent('domready', function() {
/* example a:  top down */
$$('#a a').each(function(el) {
//fx
var fx = new Fx.Tween(el,{
duration: 600,
link: 'cancel'
});				
//css & events
el.setStyle('background-position','-20px 35px').addEvents({
'mouseenter': function(e) {
e.stop();
fx.start('background-position','-20px 94px');
},
'mouseleave': function(e) {
e.stop();
fx.start('background-position','-20px 35px');
}
});
});
});