Untitled Document

header

#header{
margin-left: 50px;
padding: 20px;
width: 1100px;
height: 200px;
background-color: #DFDFDF;
position: relative;
}

#navegacao{ margin: 0; padding: 0; position: absolute; bottom: 0; left: 0; width: 100%; height: 40px; background-color:#FF6600; }

#um{
margin: 0;
padding: 10px;
width: 360px;
height: 1000px;
margin-left: 50px;
background-color: #EEEEEE;
float: left;
}

#dois{
margin: 0;
padding: 10px;
width: 360px;
height: 1000px;
background-color: #999999;
float: left;
}

#tres{
margin: 0;
padding: 10px;
width: 360px;
height: 1000px;
background-color:  #EEEEEE;
float: left;
}

rodapé!

#rodape{
width: 1100px;
height: 200px;
margin: 0;
padding: 20px;
background-color: #DFDFDF;
margin-left: 50px;
clear: both;
}