html, body {
    width:100%;
    height:100%;
    padding: 0px;
    margin: 0px;
}

#table {
   width: 100%;
   height: 100%;
   position: static;
   display: table;
   *overflow: hidden; /* hack para o IE6 e IE7 */
   *position: relative; /* hack para o IE6 e IE7 */
}

#cell {
	vertical-align: middle;
    display: table-cell;
    position: static;
    *top: 50%; /* hack para o IE6 e IE7 */
    *position: absolute; /* hack para o IE6 e IE7 */
}

#conteudo {
    top: -50%;
    width: 500px;
    margin: auto;
    position: relative;
    background: red;
}