bu kodu yazar.php olarak kaydet ve tema anadizinine yükle.

<?php
$cache_ismi = "side-yazar";
$cache_zamani = 600 * 10; 
if(false === get_transient($cache_ismi)){
ob_start();
?>
		<?php	
		echo '
		<h3 class="yanbaslik"><span>Yazarlar</span></h3>
		<div class="yan-kutu">
		<ul id="yazarlar">
		';	
		global $wpdb;	
		$fs_ayarlama = '99999';	
		if($fs_ayarlama=="")
		{	
			$fs_ayarlama = "9999999999999999999999";	
		}	
		$authors = $wpdb->get_results("SELECT ID, user_nicename from $wpdb->users WHERE ID NOT IN($fs_ayarlama) ORDER BY display_name");	
		foreach($authors as $author) 
			{
        $user_info = get_userdata($author->ID);
        $user_level = $user_info->user_level;
		if($user_level > 1) {
        echo '
		<li>
		'.get_avatar($author->ID, '48').'
		<span class="yazarimiz"><a href="'.home_url().'/?author='.$author->ID.'">'.get_the_author_meta('display_name', $author->ID).'</a></span>';		
		query_posts('author='.$author->ID.'&showposts=1');	
		
		if ( have_posts() ) : while ( have_posts() ) : the_post();	
		echo'<span class="yazarimiz-yazi"><a href="'.get_permalink().'">';
		echo get_the_title();
		endwhile; else : echo '-'; endif;		
		echo '</a></span></li>';		
			}
        }
		wp_reset_query();		
		echo '</ul></div>';  ?>
<?php
set_transient($cache_ismi, ob_get_contents(), $cache_zamani);
ob_end_flush();
}else{
echo get_transient($cache_ismi);
}
?>

Gereken style değerleri aşağıda..

h3.yanbaslik
{
width: 266px;
height: 40px;
background: url('../images/haber-sprite.png') no-repeat -0px -85px;
background-color:#a96464;
margin-top:10px;
border:1px solid rgba(0, 0, 0, 0.14);
}
h3.yanbaslik span
{
font:15px/40px 'NeoSansPro-Regular';
color:#fff;
display:block;
margin-left:10px;
}
div.yan-kutu
{
border: 1px solid #c5c1c1;
display: inline-block;
background: #f9f9f9;
padding: 5px;
width: 256px;
}

#yazarlar li span.yazarimiz a
{
color:#313131;
font:Bold 11px 'NeoSansPro-Regular';
margin-bottom:3px;
display:block;
}
#yazarlar li span.yazarimiz-yazi a
{
color:#34398e;
font:11px 'NeoSansPro-Regular';
}
#yazarlar li span.yazarimiz a:hover, #yazarlar li span.yazarimiz-yazi a:hover
{
color:#000;
}

Yan menüde nerede göstermek istiyorsan oraya şu kodu yaz;

<?php include (TEMPLATEPATH . '/yazar.php'); ?>