Index: wp-admin/network/themes.php
===================================================================
--- wp-admin/network/themes.php	(revision 16119)
+++ wp-admin/network/themes.php	(working copy)
@@ -67,6 +67,15 @@
 
 add_screen_option( 'per_page', array('label' => _x( 'Themes', 'themes per page (screen options)' ), 'default' => 999) );
 
+add_contextual_help($current_screen, 
+	'<p>' . __('This screen enables and disables the inclusion of themes available to choose in the Appearance menu for each site. It does not activate or deactivate which theme a site is currently using.') . '</p>' . 
+	'<p>' . __('If the network admin disables a theme that is in use, it can still remain selected on that site. If another theme is chosen, the disabled theme will not appear in the site&#8217;s Appearance > Themes screen.') . '</p>' . 
+	'<p>' . __('Themes can be enabled on a site by site basis by the network admin on the Edit Site screen you go to via the Edit action link on the Sites screen.') . '</p>' . 
+	'<p><strong>' . __('For more information:') . '</strong></p>' . 
+	'<p>' . __('<a href="http://codex.wordpress.org/Super_Admin_Themes_SubPanel" target="_blank">Documentation on Network Themes</a>') . '</p>' . 
+	'<p>' . __('<a href="http://wordpress.org/support/" target="_blank">Support Forums</a>') . '</p>' 
+);
+
 $title = __('Themes');
 $parent_file = 'themes.php';