Custom Post Type sorted by Title

Try…

add_filter("posts_orderby", "my_orderby_filter", 10, 2);

function my_orderby_filter($orderby, &$query){
    global $wpdb;
    //figure out whether you want to change the order
    if (get_query_var("post_type") == "my_post_type") {
         return "$wpdb->posts.post_title ASC";
    }
    return $orderby;
 }