Centrowanie w div

<style>
div {
     height: 500px;
     width: 500px;
     text-align: center;
     color: #fff;
     text-transform: uppercase;
     background: black;
     display: table;
}
div span {
     display: table-cell;
     vertical-align: middle;
}

</style>
<!--[if lte IE 7]><style>

div span {
      display: inline-block;
}

b {
      display: inline-block;
      height: 100%;
      vertical-align: middle;
}
</style><![endif]-->
<div>
<span>Jakiś sobie tam tekst <br />łamliwy tekst :)</span>
<!--[if lte IE 7]><b></b><![endif]-->
</div>
</span>