--- webform.module.orig	2009-11-05 18:01:01.000000000 -0800
+++ webform.module	2009-11-08 14:00:25.000000000 -0800
@@ -830,9 +830,10 @@ function webform_form(&$node, &$param) {
     '#type' => 'select',
     '#options' => array(
       '-1' => t('ever'),
-      '1600' => t('every hour'),
+      '3600' => t('every hour'),
       '86400' => t('every day'),
       '604800' => t('every week'),
+      '2592000' => t('every month (30 days)'),
     ),
     '#default_value' => $node->webform['submit_interval'],
     '#parents' => array('webform', 'submit_interval'),