I'd assume that the best place to go through such content would be through the provider itself. They'll sell the material that you'll need to learn, and if you look elsewhere you'll run the risk of not learning the material required for your exam.
Personally, I'd say that web design/development certification isn't worth anything, as regardless of all the certifications you own you'll be judged solely on your skills, things you'll pick up far easier working and learning yourself. I've known people graduate from universities with degrees in Web Design that code and design worse than people that have spent a week on this forum.
If I were you I'd ditch the certification as no employer will care. Just spend the time learning it yourself and build up a credible portfolio of work.