Add renaming notices to 2.6 dbm module docs.
diff --git a/Doc/library/dumbdbm.rst b/Doc/library/dumbdbm.rst
index 3db9fda..a511855 100644
--- a/Doc/library/dumbdbm.rst
+++ b/Doc/library/dumbdbm.rst
@@ -1,10 +1,13 @@
-
 :mod:`dumbdbm` --- Portable DBM implementation
 ==============================================
 
 .. module:: dumbdbm
    :synopsis: Portable implementation of the simple DBM interface.
 
+.. note::
+   The :mod:`dumbdbm` module has been renamed to :mod:`dbm.dumb` in Python 3.0.
+   The :term:`2to3` tool will automatically adapt imports when converting your
+   sources to 3.0.
 
 .. index:: single: databases