Rob Allen has some very brief notes posted today on how to use a View Helper in the Zend Framework:

This is how it works: views/helpers/MyHelper.php contains class Zend_View_Helper_MyHelper which has a function called myHelper()

Also, if you add a function called setView() to your class, then the View will pass you an instance of itself before it calls your view helper function.

A code example is included to illustrate. Check out is page in the Zend Framework manual for even more info on these handy helpers.