PHPExcel and Text Wrapping

$objPHPExcel->getDefaultStyle()->getAlignment()->setWrapText(true);

Apply to a range:

$objPHPExcel->getActiveSheet()->getStyle('D1:E999')
    ->getAlignment()->setWrapText(true); 

Apply to a column

$objPHPExcel->getActiveSheet()->getStyle('D1:D'.$objPHPExcel->getActiveSheet()->getHighestRow())
    ->getAlignment()->setWrapText(true);