--- sites/all/modules/contrib/privatemsg/pm_email_notify/pm_email_notify.admin.inc 
+++ sites/all/modules/contrib/privatemsg/pm_email_notify/pm_email_notify.admin.inc 
@@ -30,6 +30,14 @@
     '#weight' => 1,
   );
 
+  $form['pm_email']['pm_email_notify_from'] = array(
+    '#type' => 'textfield',
+    '#title' => t('From address for notifications'),
+    '#default_value' => variable_get('pm_email_notify_from',''),
+    '#weight' => 2,
+    '#description' => 'This is the email address that notifications will come from. Leave blank to use the site default.',
+  );
+
   $form['pm_email']['pm_email_notify_subject'] = array(
     '#type' => 'textfield',
     '#title' => t('Subject of notification messages'),