how to implement parallax scrolling?

this is link For reference
http://readwrite.com/2013/02/07/robert-scoble-favorite-apps-facebook-gmail-youtube
in this site Center and Right Section both are scrolled at a time if we scroll Center section...
i am done it same with this code:-

this is html code:-

<div id="left" class="linked">
<img height="600" src="http://www.visitingdc.com/images/eiffel-tower-picture.jpg">
</div>
<div id="right" class="linked">
<img  src="http://www.visitingdc.com/images/eiffel-tower-picture.jpg">
</div><br>

Script:-

$(function(){

    $('.linked').scroll(function(){
        $('.linked').scrollTop($(this).scrollTop());    
    })

})

css:-

<br>#left { width: 300px; height: 400px; overflow: scroll; float: left; }
#right { width: 300px; height: 400px; overflow: scroll; float: left; }

but i have one little bit problem.
in above site both scroll at a time but the Right side is Scrolling slow how its work....?
Please help me...