--- post.php.ori	2010-04-14 15:20:16.000000000 +0200
+++ post.php	2010-04-15 10:51:35.262489200 +0200
@@ -692,6 +692,22 @@
 }
 
 /**
+ * Check if the current or specified post is a post type
+ *
+ * @since 3.0
+ * @uses get_post_type()
+ *
+ * @param string|array $types Type or types to check. Defaults to all post types.
+ * @param int $id Post ID. Defaults to current ID.
+ * @return bool
+ */
+function is_post_type( $types = false, $id = false ) {
+	if ( $types === false )
+		$types = get_post_types();
+	return in_array( get_post_type( $id ), (array) $types );
+}
+
+/**
  * Retrieve the post type of the current post or of a given post.
  *
  * @since 2.1.0