Index: Misc/NEWS
===================================================================
--- Misc/NEWS	(revision 63753)
+++ Misc/NEWS	(working copy)
@@ -63,6 +63,9 @@
 Library
 -------
 
+- The UserString.MutableString class has been deprecated for removal
+  in Python 3.0.
+
 - Do not close external file objects passed to tarfile.open(mode='w:bz2')
   when the TarFile is closed.
 
Index: Doc/library/userdict.rst
===================================================================
--- Doc/library/userdict.rst	(revision 63753)
+++ Doc/library/userdict.rst	(working copy)
@@ -154,6 +154,11 @@
 string or Unicode objects; this is especially the case for
 :class:`MutableString`.
 
+.. warning::
+
+   In 3.0, :class:`MutableString` has been removed.  Also, :class:`UserString`
+   has been moved to the :mod:`collections` module.
+
 The :mod:`UserString` module defines the following classes:
 
 
@@ -178,6 +183,9 @@
    mutable object as dictionary key, which would be otherwise very error prone and
    hard to track down.
 
+   .. deprecated:: 2.6
+      The :class:`MutableString` class has been removed in Python 3.0.
+
 In addition to supporting the methods and operations of string and Unicode
 objects (see section :ref:`string-methods`), :class:`UserString` instances
 provide the following attribute:
Index: Lib/UserString.py
===================================================================
--- Lib/UserString.py	(revision 63753)
+++ Lib/UserString.py	(working copy)
@@ -7,6 +7,7 @@
 """
 import sys
 import collections
+from warnings import warnpy3k
 
 __all__ = ["UserString","MutableString"]
 
@@ -146,6 +147,8 @@
 
     A faster and better solution is to rewrite your program using lists."""
     def __init__(self, string=""):
+        warnpy3k("the MutableString class has been removed in Python 3.0",
+                 stacklevel=2)
         self.data = string
     def __hash__(self):
         raise TypeError, "unhashable type (it is mutable)"
Index: Lib/test/test_py3kwarn.py
===================================================================
--- Lib/test/test_py3kwarn.py	(revision 63753)
+++ Lib/test/test_py3kwarn.py	(working copy)
@@ -219,6 +219,12 @@
                 func = getattr(commands, name)
                 self.assertRaises(DeprecationWarning, func, *([None]*arg_count))
 
+    def test_userstring_mutablestring(self):
+        import UserString
+        with catch_warning(record=False):
+            warnings.filterwarnings("error")
+            self.assertRaises(DeprecationWarning, UserString.MutableString)
+        
 
 def test_main():
     with catch_warning(record=True):
Index: Lib/test/test_userstring.py
===================================================================
--- Lib/test/test_userstring.py	(revision 63753)
+++ Lib/test/test_userstring.py	(working copy)
@@ -7,6 +7,9 @@
 
 from UserString import UserString, MutableString
 
+from warnings import filterwarnings
+filterwarnings("ignore", "the MutableString class", DeprecationWarning)
+
 class UserStringTest(
     string_tests.CommonTest,
     string_tests.MixinStrUnicodeUserStringTest,