=== modified file 'uc_usps/uc_usps.module'
--- uc_usps/uc_usps.module	2007-09-05 13:47:45 +0000
+++ uc_usps/uc_usps.module	2007-09-10 13:14:12 +0000
@@ -277,6 +277,9 @@
       else{
         foreach ($package->postage as $postage){
           $attr = $postage->attributes();
+          if ($attr['classid'] === 0){
+            $attr['classid'] = 'zero';
+          }
           $services[$attr['classid']]['label'] = $postage->mailservice[0]->data();
           $services[$attr['classid']]['rate'] += uc_usps_markup($postage->rate[0]->data());
         }
@@ -387,7 +390,7 @@
 
 function _uc_usps_services(){
   return array(
-    0 => t('U.S.P.S. First-Class'),
+    'zero' => t('U.S.P.S. First-Class'),
     1 => t('U.S.P.S. Priority Mail'),
     2 => t('U.S.P.S. Express Mail PO to PO'),
     3 => t('U.S.P.S. Express Mail PO to Addressee'),