Index: wp-includes/capabilities.php
===================================================================
--- wp-includes/capabilities.php	(revision 11906)
+++ wp-includes/capabilities.php	(working copy)
@@ -699,8 +699,10 @@
 	 * @return bool True, if user has capability; false, if user does not have capability.
 	 */
 	function has_cap( $cap ) {
-		if ( is_numeric( $cap ) )
+		if ( is_numeric( $cap ) ) {
 			$cap = $this->translate_level_to_cap( $cap );
+			_deprecated_function(__('Usage of User Levels by Plugins and Themes'), '2.0', __('Roles and Capabilities') );
+		}
 
 		$args = array_slice( func_get_args(), 1 );
 		$args = array_merge( array( $cap, $this->ID ), $args );