diff -r 8c5b845c14fc lib2to3/fixes/fix_metaclass.py
--- a/lib2to3/fixes/fix_metaclass.py	Wed Feb 24 02:21:34 2010 +0000
+++ b/lib2to3/fixes/fix_metaclass.py	Sat Jan 29 19:30:13 2011 +0100
@@ -39,6 +39,9 @@
                 if isinstance(left_side, Leaf) and \
                         left_side.value == '__metaclass__':
                     return True
+        elif node.type in (syms.classdef, syms.funcdef):
+            if node.children[1].value == '__metaclass__':
+                return True
     return False
 
 
@@ -118,6 +121,9 @@
                     fixup_simple_stmt(node, i, simple_node)
                     remove_trailing_newline(simple_node)
                     yield (node, i, simple_node)
+        elif simple_node.type in (syms.classdef, syms.funcdef):
+            if simple_node.children[1].value == '__metaclass__':
+                yield (node, i, simple_node)
 
 
 def fixup_indent(suite):
@@ -157,9 +163,15 @@
         # find metaclasses, keep the last one
         last_metaclass = None
         for suite, i, stmt in find_metas(node):
-            last_metaclass = stmt
-            stmt.remove()
-
+            if stmt.type == syms.classdef:
+                self.warning(stmt, "cannot convert class __metaclass__ ...")
+            elif stmt.type == syms.funcdef:
+                self.warning(stmt, "cannot convert def __metaclass__ ...")
+            else:
+                last_metaclass = stmt
+                stmt.remove()
+        if not last_metaclass:
+            return
         text_type = node.children[0].type # always Leaf(nnn, 'class')
 
         # figure out what kind of classdef we have