A new post on the Zend Developer Zone talks about the Zend Certified Engineer oDesk site that has been set up. oDesk is a marketplace for "providers" (programmers/development shops) to interact with "buyers" (companies looking for their services).
Recently oDesk set up a group called Zend Certified Engineers and they require verification of eligibility via the providers certified ZCE ID #s in order to join this group. Why is oDesk interested in providing a ZCE group to their users? Primarily this came about because buyers of software services who are part of the oDesk ecosystem requested from oDesk better ways of distinguishing experienced, trained programmers from those who are not as knowledgeable.
You can check out a few different pages for more information - the oDesk trends page for PHP, the main page for the ZCE group and a link back to Zend's site for more information on becoming a Zend Certified Engineer.