Index: wp-admin/admin-header.php
===================================================================
--- wp-admin/admin-header.php	(revision 19692)
+++ wp-admin/admin-header.php	(working copy)
@@ -22,9 +22,9 @@
 $title = esc_html( strip_tags( $title ) );
 
 if ( is_network_admin() )
-	$admin_title = __( 'Network Admin' );
+	$admin_title = sprintf( __('Network Admin: %s'), esc_html( $current_site->site_name ) );
 elseif ( is_user_admin() )
-	$admin_title = __( 'Global Dashboard' );
+	$admin_title = sprintf( __('Global Dashboard: %s'), esc_html( $current_site->site_name ) );
 else
 	$admin_title = get_bloginfo( 'name' );