sanji41 - 10:22 am on Oct 13, 2010 (gmt 0)

here it is:
body{
width:100%;
margin:0;padding:0;
}
#wrapper{
width:960px;
}
#div1{
width:300px;
float:left;
}
#div2{
width:300px;
margin-left:300px;
}
#div3{
width:300px;
float:right;
margin-right:40px;
}
<!--try to arrange the div margin and padding. remember the 960px width of wrapper.-->
<div id="wrapper">
<div id="div1">
</div>
<div id="div2">
</div>
<div id="div3">
</div>
</div>