Sometimes you are asked to add a second submit button above each node form.
This can be easily done with a few lines of code:

secondsubmit.info

; $Id$
name = "Second submit"
description = "Second submit button on node forms."
core = "6.x"

secondsubmit.module

// $Id$

/**
 * @file
 * Module definition for secondsubmit.
 */

/**
 * Implement hook_form_alter().
 */
function secondsubmit_form_alter(&$form, $form_state, $form_id) {
  // Add a second submit button to node forms.
  if ($form['#node'] && ($form_id == $form['#node']->type . '_node_form')) {
     $form['secondsubmit'] = array(
        '#type' => 'submit',
        '#value' => t('Save & continue'),
        '#weight' => -10,
        '#validate' => array('node_form_validate'),
        // Use default and an additional submit handler.
        '#submit' => array('node_form_submit', 'additional_node_form_submit'),
      );
  }
}

/**
 * Implement of additional form submit
 */
function additional_node_form_submit($form, &$form_state) {
  // ...
}