You would start by checking out their site, which Mogul posted. A friend of mine, who just celebrated his 40th year as a studio owner, is a member and holds several degrees from them. I know he gets called upon to judge professional competitions. He is also quite successful in his work and is more knowledgeable about photography then anyone I have ever met. I don't know if any of that has anything to do with his membership in the PPA, but it certainly does not seem to have hurt him.
I have two friends with the PPA credentials. You work you ass of to prove you know your shit across the spectrum to get certified.
And some people think that just a high school education is all you need to get a job.