$(function () {

    $('.menu a')
        .css({ backgroundPosition: "0 0" })
        .mouseover(function () {
    	    $(this).stop().animate(
    		    { backgroundPosition: "(0 -250px)" },
    		    { duration: 500 })
        })
        .mouseout(function () {
    	    $(this).stop().animate(
    		    { backgroundPosition: "(0 0)" },
    		    { duration: 500 })
        });
});