The docs are great if you know PHP, if not they may as well be written in moon-speak. I struggled to get the relate field to print out a nice list of links in my theme. The example in the docs just prints out the post titles – no urls / permalinks. Here’s how I managed to do it.

First, create your field-

<?php
/*
Title: Add links to other useful posts
Post Type: post
*/

piklist('field', array(
'type' => 'post-relate'
,'scope' => 'post'
,'template' => 'field'
));

Next, go ahead and create a test post and add some related posts to your new field.

Now open up the theme file that displays your single posts (single.php). You’ll find some moon-speak similar to the following:

<?php
// Start the loop.
while ( have_posts() ) : the_post();

// Some more moon-speak that prints out the post - removed for brevity. 
			
// End of the loop.
endwhile; ?>

Before the end of your post loop, add the following:

<?php         
$related = get_posts(array(
'post_type' => 'posts' // Set post type you are relating to.
,'posts_per_page' => -1
,'post_belongs' => $post->ID
,'post_status' => 'publish'
,'suppress_filters' => false // This must be set to false
));
?>

<ul>
<?php foreach($related as $related_post) {
echo '<li><a href="'.get_post_permalink($related_post->ID).'">'.$related_post->post_title.'</a></li>';
} ?>
</ul>

Viola! A nice list of links to your related posts. Please note this doesn’t work outside of the main post loop. So no trying to stick it in your sidebar. If anyone knows how to get this to work outside of the loop, I’d love to know!