I have been looking for sites that offer some form of certification for those intending to work as search engine optimizers. There are a few around, and they look very good. However, most cost several hundred dollars US at the very least. There are two that are much more affordable, however, and they can be found at Expert Rating, and SEO Certification.
I know a lot of the more experienced webmasters and bloggers would look down on these qualifications as meaningless. It's easy to read a few lessons, then regurgitate them in an online test, after all. The real test of someone's knowledge and skill comes when they have to get a site to the top of the SERPs. And only a lot of experience promoting websites and blogs will prepare someone for that.
That said, I believe that qualifications can't do any harm. It's always good to have gone through some sort of structured course, however basic and brief. And having such qualifications definitely inspires confidence in prospective customers.