RelatedPost Wordpress by category

<!-- related post -->
<?php
$orig_post = $post;
global $post;
$categories = get_the_category($post->ID);
if ($categories) {
$category_ids = array();
foreach($categories as $individual_category) $category_ids[] = $individual_category->term_id;
$args=array(
'category__in' => $category_ids,
'post__not_in' => array($post->ID),
'posts_per_page'=> 10, // Number of related posts that will be shown.
'caller_get_posts'=>1
);
$my_query = new wp_query( $args );
if( $my_query->have_posts() ) {
echo '<div class="sidebar-widget"><div class="title_sidebar">Artikel Terkait</div><ul>';
while( $my_query->have_posts() ) {
$my_query->the_post();?>
<li><a href="<? the_permalink()?>" rel="bookmark" title="<?php the_title(); ?>"><?php the_title(); ?></a></li>
<?
}
echo '</ul></div>';
}
}
$post = $orig_post;
wp_reset_query();
?>