This WordPress snippet will let you show a list of posts by a specific user. This is useful if you, for example, want to show a list of posts from a specific user on Custom Post Types, etc.

Instructions
1. Add a Custom Field (read more about WordPress Custom Fields) to the Page or Custom Post Type etc. In that custom field add “user-id” as the name and the numeric value “1” (or whatever the ID of the specific user is) as the Value“.

2. Add the following to your template.php file

<?php $the_user_id = get_post_meta( $post->ID, 'user-id', true); if ($the_user_id) { ?>
     <?php query_posts("author=$the_user_id&posts_per_page=5" );?>
          <ul>
               <?php if (have_posts()) : while (have_posts()) : the_post(); ?>
                    <li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a><br><?php the_excerpt() ?></li>      
               <?php endwhile; else: ?>
          </ul>
          <p><?php _e('No posts by this user-id'); ?></p>
          <?php endif; ?>
     <?php wp_reset_query(); ?>
<?php } else { ?>
     <!-- No value ha been set for the Custom Field "user-id" -->
<?php } ?>