Here you go. Should work in all browsers except IE7 and earlier.

You can add as many column divs as you like.

Note that the html { height:100% } is needed when in HTML5 mode.

  <!DOCTYPE HTML>
  <html>
    <head>
      <style type="text/css">
        html, body { height:100%; margin: 0 auto; }
        body { display: table; vertical-align: middle; }
        .column { display:table-cell; vertical-align: middle; }
        p { text-align: center; }
      </style>
    </head>
    <body>
      <div class="column">
        <p>holy cow!</p>
        <img alt="shock the monkey" src="http://i.imgur.com/Pt9Pd.jpg" />
        <p>it worked!</p>
      </div>
    </body>
  </html>