hola te de un ejemplo de centrado vertical:
Código HTML:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<head>
<style type="text/css">
.contenedor-link {
width: 100px;
border: #000 solid 1px;
height: 100px;
color:#00CCFF;
font-family:Georgia, "Times New Roman", Times, serif;
font-size:20px;
}
.contenedor-link[class] {
display: table;}
.centrado {
position: absolute;
top: 50%;}
.centrado[class] {
display: table-cell;
vertical-align: middle;
text-align: center;
position: static;
}
.link{
width: 100px;
height:auto;
margin: 0 auto;
position: relative;
top: -50%;
}
</style>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<div class="contenedor-link">
<div class="centrado">
<div class="link">link</div>
</div>
</div>
</body>
</html>