Index: django/http/__init__.py
===================================================================
--- django/http/__init__.py	(revision 7127)
+++ django/http/__init__.py	(working copy)
@@ -1,4 +1,5 @@
 import os
+import re
 from Cookie import SimpleCookie
 from pprint import pformat
 from urllib import urlencode
@@ -8,6 +9,7 @@
 from utils import *
 
 RESERVED_CHARS="!*'();:@&=+$,/?%#[]"
+ABS_URI_RE = re.compile('^https?:')
 
 try:
     # The mod_python version is more efficient, so try importing it first.
@@ -71,7 +73,7 @@
         """
         if not location:
             location = self.get_full_path()
-        if not ':' in location:
+        if not ABS_URI_RE.match(location):
             current_uri = '%s://%s%s' % (self.is_secure() and 'https' or 'http',
                                          self.get_host(), self.path)
             location = urljoin(current_uri, location)