jQuery(document).ready(function(){
$("#iconbar li .base").hover(
function(){
$(this).animate({opacity: "hide"}, "slow");
$(this).next().animate({opacity: "show"}, "slow");

//code for showing span goes here...
},
function(){
//nothing here because it will never be triggered.
}
);
$("#iconbar li .hover").hover(
function(){
//nothing here because it will never be triggered.
},
function(){
$(this).animate({opacity: "hide"}, "slow");
$(this).prev().animate({opacity: "show"}, "slow");
//code for hiding span goes here...
}
);

});