Kevin Schroeder's Blog: Integrating Zend_View with WordPress
Kevin Schroeder has a recent post to his blog showing how he integrated Zend_View into a WordPress install for his blog. It was as a part of a plugin he uses on some of his internal pages.
I just read a blog post about integrating Zend Framework and WordPress and figured I'd add some commentary of my own, since I've done something similar. In my ESchrade plugin I use Zend_View to render some of my admin pages, though there is no reason why you couldn't use it elsewhere, as long as the plugin has already been loaded.
Adding the functionality is easy as long as the Zend Framework install is in your include path. He gives some sample code that creates the view object, defining the templates path and pulling in the "wp_register_sidebar_widget" WordPress method to import the view.