[Plugin: List category posts] See posts list from current categorie

Might consider using something like this in your theme template that displays posts–for each category of that post i.e. related, display 5 posts in that category, excluding the single post.

<?php
  $categories = get_the_category();
  if ($categories) {
    foreach ($categories as $category) {
      $cat = $category->cat_ID;
      $args=array(
        'cat' => $cat,
        'post__not_in' => array($post->ID),
        'posts_per_page'=>5,
        'caller_get_posts'=>1
      );
      $my_query = null;
      $my_query = new WP_Query($args);
      if( $my_query->have_posts() ) {
        echo '<h2>More Posts from '. $category->category_description . '</h2>';
        while ($my_query->have_posts()) : $my_query->the_post(); ?>
          <p><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></p>
         <?php
        endwhile;
      } //if ($my_query)
    } //foreach ($categories
  } //if ($categories)
  wp_reset_query();  // Restore global post data stomped by the_post().
?>