Your login function would be something like
public function login() {
if ($this->request->is('post')) {
if ($this->Auth->login()) {
$userType = $this->Auth->user('type');
if ($userType == 'admin') {
$this->redirect(array('controller' => 'admin', 'action' => 'dashboard'));
} else {
$this->redirect(array('controller' => 'users', 'action' => 'profile'));
}
} else {
$this->Session->setFlash(__('Invalid username or password, try again'));
}
}
}