Set custom messages for post update/save

http://codex.wordpress.org/Function_Reference/register_post_type
example:

    //add filter to ensure the text Book, or book, is displayed when user updates a book 
add_filter('post_updated_messages', 'codex_book_updated_messages');
function codex_book_updated_messages( $messages ) {
  global $post, $post_ID;

  $messages['book'] = array(
    0 => '', // Unused. Messages start at index 1.
    1 => sprintf( __('Book updated. <a href="https://wordpress.stackexchange.com/questions/17885/%s">View book</a>'), esc_url( get_permalink($post_ID) ) ),
    2 => __('Custom field updated.'),
    3 => __('Custom field deleted.'),
    4 => __('Book updated.'),
    /* translators: %s: date and time of the revision */
    5 => isset($_GET['revision']) ? sprintf( __('Book restored to revision from %s'), wp_post_revision_title( (int) $_GET['revision'], false ) ) : false,
    6 => sprintf( __('Book published. <a href="https://wordpress.stackexchange.com/questions/17885/%s">View book</a>'), esc_url( get_permalink($post_ID) ) ),
    7 => __('Book saved.'),
    8 => sprintf( __('Book submitted. <a target="_blank" href="https://wordpress.stackexchange.com/questions/17885/%s">Preview book</a>'), esc_url( add_query_arg( 'preview', 'true', get_permalink($post_ID) ) ) ),
    9 => sprintf( __('Book scheduled for: <strong>%1$s</strong>. <a target="_blank" href="%2$s">Preview book</a>'),
      // translators: Publish box date format, see http://php.net/date
      date_i18n( __( 'M j, Y @ G:i' ), strtotime( $post->post_date ) ), esc_url( get_permalink($post_ID) ) ),
    10 => sprintf( __('Book draft updated. <a target="_blank" href="https://wordpress.stackexchange.com/questions/17885/%s">Preview book</a>'), esc_url( add_query_arg( 'preview', 'true', get_permalink($post_ID) ) ) ),
  );

  return $messages;
}