Sample Comment Walker for WordPress

function.extra_comment_callback.php

<?php
/**
 * Callback for wp_list_comments()
 * @param  object $comment
 * @param  array  $args
 * @param  int    $depth
 * @return void
 */
function extra_comment_callback( $comment, $args, $depth )
{
	$GLOBALS['comment'] = $comment;
?>
<li <?php comment_class(); ?> id="li-comment-<?php comment_ID() ?>">
	<div id="comment-<?php comment_ID(); ?>">
<?php if ( $comment->comment_approved == '0' )
{
?>
	<p class="approval-notice"><?php
	print get_theme_mod(
		'text_moderation_notice'
	,	'Ihr Kommentar wird moderiert. Bitte haben Sie etwas Geduld.'
	);
	?></p>
<?php
}
	if ( 'pingback' == $comment->comment_type or 'trackback' == $comment->comment_type )
	{
		#pre_dump( $comment );
		print 'Link: ' . get_comment_author_link( get_comment_ID() );
		edit_comment_link( 'Bearbeiten', ' · ' );
		comment_text( get_comment_ID() );
	}
	else
	{
	comment_text( get_comment_ID() );
	?>
		<div class="comment-author vcard reply">
			<?php comment_author_link(); ?> |
			<?php printf( '%1$s | %2$s', get_comment_date(), get_comment_time() );

			if ( 0 == $depth || $args['max_depth'] <= $depth )
			{
				$depth += 1;
				$args['max_depth'] +=2;
			}

		comment_reply_link(
			array_merge(
				$args,
				array(
					'depth'     => $depth
				,	'max_depth' => $args['max_depth']
				,	'before'    => ' | '
				,	'after'     => ''
				)
			)
		);
		edit_comment_link( 'Bearbeiten', ' | ' );
		?>
		</div>
		<?php
	}
		?>
	</div>
<?php
	// the closing </li> will be inserted by WordPress.
}

See http://blog.zdf.de/hyperland/2011/06/dieter-gorny-wir-muessen-reden/#comments for a live example.