Before, you could become a pharmacist by just getting a bachelors in pharmacy (of course, after taking the exams and getting licensed). They changed that and now require people to go to pharmacy school and get your PharmD. All pharmacists are registered pharmacists, it's just that RPh's didn't get their PharmD. You'll notice a lot of the older pharmacists are RPh's, but just because they don't have a PharmD it doesn't mean they don't know what they're doing. They just don't have $100,000 in loans to pay off, probably haha.
In 2000, the ACPE, which is the accrediting board for pharmacy schools detemined the entry level degree for pharmacist education would be the PharmD. Prior to that the educational degree was dependent upon the school and state....both a BS & PharmD degrees were awarded. These are academic degrees.
The RPh indicates the individual has sucessfully passed the state board exam in which it was taken. It denotes licensure.
A pharmacist can have a BS or PharmD with or without an RPh, but an RPh must have a BS or PharmD.