class WebsiteController extends CController
{
   function actionOk()
   {
      Yii::app()->user->setFlash('success', 'Everything went fine!');
      $this->redirect('index');
   }

   function actionBad()
   {
      Yii::app()->user->setFlash('error', 'Everything went wrong!');
      $this->redirect('index');
   }

   function actionIndex()
   {
      $this->render('index');
   }
}

<?php if(Yii::app()->user->hasFlash('success')):?>
<div class="flash-notice">
   <?php echo Yii::app()->user->getFlash('success')?>
</div>
<?php endif?>
<?php if(Yii::app()->user->hasFlash('error')):?>
<div class="flash-error">
   <?php echo Yii::app()->user->getFlash('error')?>
</div>
<?php endif?>