$(document).ready(function (){
  var animationDelay = 150;
  $('#header li a:not(.selected)').mouseover(function (){
    $(this).css('backgroundPosition','15px');
    $(this).animate({
      backgroundPosition: '0px'
    },animationDelay);
  }).mouseout(function (){
    $(this).css('backgroundPosition','0px');
    $(this).animate({
      backgroundPosition: '15px'
    },animationDelay);
  });
});