Index: simplenews.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/simplenews/simplenews.module,v
retrieving revision 1.151
diff -u -p -r1.151 simplenews.module
--- simplenews.module	21 Sep 2008 13:51:52 -0000	1.151
+++ simplenews.module	21 Sep 2008 14:15:20 -0000
@@ -879,7 +879,7 @@ function _simplenews_user_load($mail) {
     // Construct anonymous user since we don't have a user that matches that e-amil.
     $account = new stdClass();
     $account->uid = 0;
-    $account->mail = $mail;
+    $account->mail = drupal_strtolower($mail);
   }
   return $account;
 }