--- includes/common.inc	2010-10-18 15:28:41.000000000 -0400
+++ includes/common.incp	2010-10-18 15:25:52.000000000 -0400
@@ -1241,7 +1241,7 @@ function drupal_strip_dangerous_protocol
   static $allowed_protocols;
 
   if (!isset($allowed_protocols)) {
-    $allowed_protocols = array_flip(variable_get('filter_allowed_protocols', array('ftp', 'http', 'https', 'irc', 'mailto', 'news', 'nntp', 'rtsp', 'sftp', 'ssh', 'telnet', 'webcal')));
+    $allowed_protocols = array_flip(variable_get('filter_allowed_protocols', array('ftp', 'http', 'https', 'irc', 'mailto', 'news', 'nntp', 'rtsp', 'sftp', 'ssh', 'telnet', 'webcal', 'tel')));
   }
 
   // Iteratively remove any invalid protocol found.