Split Webform Items into two rows
Last version of webforms lets you do this outofdabox (put fields in a fieldset though)

You can also achive this using a hook_form_alter implementation (Have not tested this but i think that should work) and using the FAPI #type container element, for example:

$form['left'] = array(
  '#type' =&gt; 'container',
  '#attributes' =&gt; array(
    'class' =&gt; array(
      'left',
      drupal_html_class($class_left),
    ),
    'id' =&gt; array('lefttoleft'),
  ),
);      


Create as many container as you want and then move all fields FAPI element inside the container