In order to nicely display flash Messages, create view like this called views/site/dialog.php :

<?php
if($flashes = Yii::app()->user->getFlashes()) {
	foreach($flashes as $key => $message) {
		if($key != 'counters') {
			$this->beginWidget('zii.widgets.jui.CJuiDialog', array(
						'id'=>$key,
						'options'=>array(
							'show' => 'blind',
							'hide' => 'explode',
							'modal' => 'true',
							'title' => $message['title'],
							'autoOpen'=>true,
							),
						));

			printf('<span class="dialog">%s</span>', $message['content']);

			$this->endWidget('zii.widgets.jui.CJuiDialog');
		}
	}
}
?>

add this line before your <?php echo $content; ?> of your layout file (most probably views/layouts/main.php) :

<?php $this->renderPartial('//site/dialog'); ?>

after that, a very nice jquery ui dialog will display your flash messages.

In addition to this, i suggest a wrapper function like this:

<?php
class Dialog {
	public static function Message($title, $message, $id = 0) {
		if($id == 0)
			$id = rand(1, 999999);
		Yii::app()->user->setflash($id, array('title' => $title, 'content' => $message) );
	}
}
?>

This way you can toggle your Dialogues, even with HTML content and different Buttons inside as easy as this:

$message = 'Hello World!';
		$message .= '<br /><strong>Where do you want to go today?</strong><br />';
		$message .= CHtml::Button('Home', array('submit' => array('home/admin')));
		$message .= '<br />';
		$message .= CHtml::Button('Far far away', array('submit' => array('far/away')));
		Dialog::message('Title', $message);

or just

Dialog::message('title', 'content');

I hope this Code snippet will be useful for you. Please send any advices, suggestions or errors to thyseus@gmail.com, thank you.