On the Zend Developer Zone there's a new tutorial (by Matthew Weier O'Phinney) covering the use of decorators with the Zend_Form component of the Zend Framework.

One point of flexibility [Zend_Form] offers has proved to be a pain point for many developers: decorators. This tutorial aims to shed some light on decorators, as well as provide strategies for creating your own decorators and combining them in creative ways to customize the output your forms generate.

Matthew starts with a little background behind the component to help you find your way around. Building on this, he shows how to use some standard output decorators and how to create decorators of your own. His example shows how to create a set of grouped checkboxes.