[kh99]

You would need to put it somewhere where you can see the output. One thing you could do it make a plugin using hook misc_start and code like this:

if ($_REQUEST['do'] == 'var_dump')
{
   echo "<pre>";
   var_dump($vbulletin->userinfo);
   echo "</pre>";
   exit;
}

Then to see it go to misc.php?do=var_dump . (You'd probably want to disable the plugin when you're done).