Index: django/core/management.py
===================================================================
--- django/core/management.py   (revision 4485)
+++ django/core/management.py   (working copy)
@@ -27,6 +27,8 @@
 
 INVALID_PROJECT_NAMES = ('django', 'site', 'test')
 
+INVALID_APPLICATION_NAMES = INVALID_PROJECT_NAMES
+
 # Set up the terminal color scheme.
 class dummy: pass
 style = dummy()
@@ -726,6 +728,9 @@
     "Creates a Django app for the given app_name in the given directory."
     # Determine the project_name a bit naively -- by looking at the name of
     # the parent directory.
+    if app_name in INVALID_APPLICATION_NAMES:
+        sys.stderr.write(style.ERROR("Error: '%r' conflicts with the name of an existing Python module and cannot be used as a application name. Please try another name.\n" % app_name))
+        sys.exit(1)
     project_dir = os.path.normpath(os.path.join(directory, '..'))
     project_name = os.path.basename(project_dir)
     if app_name == os.path.basename(directory):