temanızın functions.php dosyasına:

function fb_list_authors($userlevel = 'all', $show_fullname = true) {
	global $wpdb;
	
/*
 all = Display all user
 1 = subscriber
 2 = editor
 3 = author
 7 = publisher
10 = administrator
*/

if ( $userlevel == 'all' ) {
	$author_subscriper = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_key = 'wp_capabilities' AND meta_value = 'a:1:{s:10:\"subscriber\";b:1;}'");
	foreach ( (array) $author_subscriper as $author ) {
		$author    = get_userdata( $author->user_id );
		$userlevel = $author->wp2_user_level;
		$name      = $author->nickname;
		if ( $show_fullname && ($author->first_name != '' && $author->last_name != '') ) {
			$name = "$author->first_name $author->last_name";
		}
		$link = '<li>' . $name . '</li>';
		echo $link;
	}
	
	$i = 0;
	while ( $i <= 10 ) {
		$userlevel = $i;
		$authors = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_key = 'wp_user_level' AND meta_value = '$userlevel'");
		foreach ( (array) $authors as $author ) {
			$author    = get_userdata( $author->user_id );
			$userlevel = $author->wp2_user_level;
			$name      = $author->nickname;
			if ( $show_fullname && ($author->first_name != '' && $author->last_name != '') ) {
				$name = "$author->first_name $author->last_name";
			}
			$link = '<li>' . $name . '</li>';
			echo $link;
		}
		$i++;
	}
} else {
	if ($userlevel == 1) {
		$authors = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_key = 'wp_capabilities' AND meta_value = 'a:1:{s:10:\"subscriber\";b:1;}'");
	} else {
		$authors = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_value = '$userlevel'");
	}
	foreach ( (array) $authors as $author ) {
		$author = get_userdata( $author->user_id );
		$userlevel = $author->wp2_user_level;
		$name = $author->nickname;
		if ( $show_fullname && ($author->first_name != '' && $author->last_name != '') ) {
			$name = "$author->first_name $author->last_name";
		}
		$link  = '<li><b>' . $userlevelname[$userlevel] . '</b></li>';
		$link .= '<li>' . $name . '</li>';
		echo $link;
	}
}
}

ekleyin.

daha sonra sidebar.php içerisine;

Sadece yöneticiler ve sadece kullanıcı adları için:

<ul>
<?php fb_list_authors(10, FALSE); ?>
</ul>

Tüm kullanıcılar, isim ve soyisimleriyle birlikte listelemek için:

<ol>
<?php fb_list_authors(); ?>
</ol>

Sadece aboneler, isim ve soyisimleriyle birlikte listelemek için:

<ul>
<?php fb_list_authors(1, TRUE); ?>
</ul>

kodunu ekleyin.

kaynak: http://wpengineer.com/365/list-all-users-in-wordpress/