List all users by first letter in name

Here is some sample code that does what you want:

$sql = "SELECT umfirst.meta_value AS first_name, umlast.meta_value AS last_name
FROM $wpdb->usermeta umfirst, $wpdb->usermeta umlast
WHERE umlast.meta_key = 'last_name'
AND umfirst.meta_key = 'first_name'
AND umfirst.user_id = umlast.user_id
AND umlast.meta_value LIKE 'A%'";

$rows = $wpdb->get_results($sql);
foreach ($rows as $row) {
  echo "$row->last_name, $row->first_name<br />";
}
?>

Before I work on that, I want to make sure that is all you want. Is there more?

Here is code for you to try:

// List authors by first letter of last name
$sql = "SELECT umfirst.user_id, umfirst.meta_value AS first_name, umlast.meta_value AS last_name
FROM $wpdb->usermeta umfirst, $wpdb->usermeta umlast
WHERE umlast.meta_key = 'last_name'
AND umfirst.meta_key = 'first_name'
AND umfirst.user_id = umlast.user_id
AND umlast.meta_value LIKE 'A%'
ORDER BY last_name, first_name";

$rows = $wpdb->get_results($sql);
foreach ($rows as $row) {
  $cimy_value = get_cimyFieldValue($row->user_id, 'PHONE');
  $user_data =  "$row->last_name, $row->first_name $cimy_value";
  if (is_user_logged_in()) {
    $output = "<a href=\"" . get_bloginfo('url') . '/wp-admin/user-edit.php/?user_id=' . $row->user_id  . '" alt="" >' . $user_data . '</a>';
  } else {
    $output = $user_data;
  }
  echo "$output<br />\n";
}

(note to self: from miataclub29 testphp.php)