Flash is a modest widget that allows you to render web user flash messages easily.
A newer version of this extension, TbAlert, is now part of my Bootstrap extension.
To set up the widget you simply need to download the extension, place it in your application's extensions folder (create it under protected if it doesn't exist).
Rendering the widget is easy, you need to add the following code snippet to your main layout (Assuming you placed the extensions under /protected/extensions/flash) :
<?php $this->widget('application.extensions.flash.Flash', array( 'keys'=>array('success','error'), 'htmlOptions'=>array('class'=>'flash'), )); ?><!-- flashes -->
After you've configured the widget it will display your flash messages.