Index: post.php
===================================================================
--- post.php	(revision 14085)
+++ post.php	(working copy)
@@ -683,6 +683,20 @@
 }
 
 /**
+ * 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.
+ * @param int $id Post ID. Defaults to current ID.
+ * @return bool
+ */
+function is_post_type( $types, $id = false ) {
+	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