Related Posts Tag WordPress

<div class="relatedposts">
<h3>Related posts</h3>
<?php
  $orig_post = $post;
  global $post;
  $tags = wp_get_post_tags($post->ID);

  if ($tags) {
  $tag_ids = array();
  foreach($tags as $individual_tag) $tag_ids[] = $individual_tag->term_id;
  $args=array(
  'tag__in' => $tag_ids,
  'post__not_in' => array($post->ID),
  'posts_per_page'=>4, // Number of related posts to display.
  'caller_get_posts'=>1
  );

  $my_query = new wp_query( $args );

  while( $my_query->have_posts() ) {
  $my_query->the_post();
  ?>

  <div class="relatedthumb">
    <a rel="external" href="<? the_permalink()?>"><?php the_post_thumbnail(array(150,100)); ?><br />
    <?php the_title(); ?>
    </a>
  </div>

  <? }
  }
  $post = $orig_post;
  wp_reset_query();
  ?>
</div>