How to Highlight Author Comments in  WordPress

To highlight comments posted by the author in WordPress, add the following code to the comments.php file in your WordPress template:

 // Author Comments
if (1 == $comment->user_id) { ?>
        <li id="comment-<?php comment_ID(); ?>" class="authcomment">
<?php } else { ?>
        <li id="comment-<?php comment_ID(); ?>">
<?php } 

For reference, the full comment structure I am using for kevinleary.net is:

<ol id="commentlist">
<?php foreach ($comments as $comment) : ?>

<?php // Author Comments
if (1 == $comment->user_id) { ?>
    <li id="comment-<?php comment_ID(); ?>" class="authcomment">
<?php } else { ?>
    <li id="comment-<?php comment_ID(); ?>">
<?php } ?>

        <p>
            <cite><strong class="author"><?php comment_author_link() ?></strong> / <?php comment_date() ?> / <a href="#comment-<?php comment_ID() ?>"><?php comment_time() ?></a><?php edit_comment_link(__(" / Edit")); ?></cite>
        </p>

        <div class="commentbox">
            <?php echo get_avatar( $comment, 32 ); ?>
            <?php comment_text() ?>
        </div>

    </li>

<?php endforeach; ?>
</ol>

Now simply style #commentlist li.authcomment and your done.