--- twitter.pages.inc.old	2009-01-18 07:43:53.000000000 +1100
+++ twitter.pages.inc	2009-04-01 01:35:56.000000000 +1100
@@ -208,6 +208,8 @@ function twitter_add_account($form_state
 function twitter_add_account_validate($form, &$form_state) {
   module_load_include('inc', 'twitter');
 
+  $form_state['values']['screen_name'] = strtolower($form_state['values']['screen_name']);
+
   $verify = FALSE;
 
   $pass = $form_state['values']['password'];