Aplicar margin a las tablas en explorer

[minute]

body {
text-align:center;
}


#contenedor
{

position:relative;
background-image: url(Imagenes/a.jpg);
width:990px;
height:640px;
margin: 0 auto;
text-align:left;
border: 2px solid yellow;


}



.tabla_contacto
{
font-family:calibri;
color:yellow;
margin-top:90px;
margin-left:280px;
text-align:center;
font-size:20px;




}