CSS vertical centering for IE7+

gistfile1.css

/******************************************************************************
  Vertical centering of variable-height content
  Compatible with IE7 and below

  Author: Charlie Tran
  Date: Feb 2012
  Agency: FreeAssociation (www.thinkfa.com)

  More elegant solution here if you only care about IE8+: http://goo.gl/UN80L

  Markup
  --------------------------
  <div class="vcenter-outer">
    <div class="vcenter-inner">
      <div class="vcenter-content">
        CENTERED CONTENT HERE
      </div>
    </div>
  </div>
  --------------------------

  The additional 'vcenter-content' wrapper is
  unfortunately necessary for IE7 and below compatibility
*******************************************************************************/

.vcenter-outer
{
  display: table;
  overflow: hidden;
  position: relative;
}

.vcenter-inner
{
  display: table-cell;
  vertical-align: middle;
  width: 100%;

  /* For horizontal centering, optional */
  margin: 0 auto;
  text-align: center;
}

/*******************************************************************************
  For IE7 and below, assumes use of IE-conditional HTML tags from H5BP
  http://goo.gl/CRQY (2012.01.17 update)
*******************************************************************************/

.lt-ie8 .vcenter-inner
{
  position: absolute;
  top: 50%;
}

.lt-ie8 .vcenter-content
{
  position: relative;
  top: -50%;
}

Make sure whatever element .vcenter-outer is applied to also has a defined height. Good stuff, charlie!