On the ZendCasts.com site there's a new screencast showing you how to create custom Zend filters with HTMLPurifier, the standards-compliant tool that can remove potential issues from your HTML as well as restructure it to be more along the lines of the W3C specifications.

He shows how to set up the HTMLPurifier tool into your Zend Framework application so you can use it as a filter on your view's output. He sets it up as a new filter, ZC_Filter_HTMLPurifier, and creates the basic filtering interface library to make it work.

You can find out more about using filters in Zend Framework applications in this section of the manual.