There seem to be a fair lot of Usability certification programs out there. I'm wondering if you all have any opinions as to which ones are most likely to be taken seriously by the people who write the checks.

I've been keeping up to date on usability and accessibility practices and incorporating them into all my work since long before the word "usability" was invented - I suppose I could probably teach the subject. But, what project managers and executives want to see is some kind of certification or other quantifiable proof that you can do what you say you can do.

Is there an authoritative body that governs web usability professionals and usability curriculum? (similar to, say, PMI for project management professionals.) If so, are there any specific certification programs that they endorse?

And most of all, which of said organizations and their respective certifications are what corporations hope to see on a prospective Usability Consultant's resume?