The best place, and I know from experience, is Miami Jewelry School. You will receive the best personalized training and after you are finished with the basic course you will be ready for a job in the jewelry trade. Many of my fellow students have been hired to work for jewelry businesses and companies even before graduating.
In regards to your jeweler certification question, what type of jeweler do you want to be? Do you want to make jewelry from scratch, use waxes, or be a stone setter? After you decide what you want, then think about what certificate you are after.
the school's website is www.miamijewelryschool.com