I think that generally depends on the field. For example, in the Microsoft world, everyone cares about Microsoft certifications.
As for the PHP world, if you are a freelancer then I would definately recommend taking the Zend exam if you can - it will help seperate you from the thousands of other freelance PHP developers out there and shows potential clients that you actually have some willingness to learn and the drive to progress. It also shows that you are not afraid of a challange which is what I look for in developers
I can honestly say that if I was hiring a PHP developer, and had two candidates, both of equal calliber, I would hire the one with the Zend Certification.
__________________ Programmers are in a race with the Universe to create bigger and better idiot-proof programs, while the Universe is trying to create bigger and better idiots. So far the Universe is winning. - Rich Cook
A certification in the field of programming is more important than your college degree (of course, it now depends on the level of certification). You may have gone to some great schools, but it really doesn't help at a job interview if you know nothing about programming.
Another choice is Brainbench.
I have optimistic thoughts, even though sometimes (if not always) life's a bitch.