Format::setVAlign

require_once 'Spreadsheet/Excel/Writer.php';

$workbook = new Spreadsheet_Excel_Writer();
$worksheet =& $workbook->addWorksheet();

// justify 
$format_justify =& $workbook->addFormat('vAlign' => 'vjustify');

// center the text vertically
$format_center =& $workbook->addFormat('vAlign' => 'vcenter');

// justify and center vertically
$format_justify_center =& $workbook->addFormat();
$format_justify_center->setVAlign('vjustify');
$format_justify_center->setVAlign('vcenter');

$worksheet->write(0, 0, 'justify', $format_justify);
$worksheet->write(1, 0, 'center', $format_center);
$worksheet->write(2, 0, 'jc', $format_justify_center);

$workbook->send('align.xls');
$workbook->close();