Action:

$this->results = Doctrine_Query::create()
    ->select('u.*, p.name, p.sort_key')
    ->from('Users u')
    ->leftJoin('u.UserPermission up')
    ->leftJoin('up.Permission p')
    ->where('u.user_id = ?')
    ->orderBy('p.sort_key')
    ->execute(array('1010'));

-------------------------------------
Template:

<?php foreach($results AS $result): ?>
  <strong><?php echo $result->get('first_name'); ?> <?php echo $result->get('last_name'); ?></strong><br />
  <br />
  <ul>
  <?php foreach($result->UserPermission AS $upermission): ?>
    <li><?php echo $upermission->Permission->get('name'); ?></li>
  <?php endforeach; ?>
  </ul>
<?php endforeach;?>