// in an action
$this->logMessage($message, $level);
// in a template
<?php echo log_message($message, $level) ?>

例:

<code>
// in a template
<?php use_helper('Debug') ?>
<?php echo log_message('{mainActions} been there', 'err') ?>
// in an action
$this->getLogger()->info($message);
$this->getLogger()->err($message);
$this->getLogger()->warning($message);
// from anywhere in your application
sfContext::getInstance()->getLogger()->info($message);
sfContext::getInstance()->getLogger()->err($message);
sfContext::getInstance()->getLogger()->warning($message);
</code>

There are 8 levels of log messages:
emerg, alert, crit, err, warning, notice, info, debug
http://www.symfony-project.com/book/trunk/debug