Provisional judge: Passed the online entry exam. Only good for one year and required in order to take the tasting exam. Not an actual certification as far as I've been told.
Recognized judge: 60 or higher on tasting exam, no experience points (judging/stewarding)
Certified judge: 70 or higher on tasting exam, 5 experience points. This is what most people are actually aiming for when they want to become a "beer judge", and the highest rank that most BJCP members achieve.
National judge: 80 or higher on tasting exam, 20 experience points, pass written exam
Master judge: 90 or higher on tasting exam, 40 experience points, pass written exam
Honorary Master, Grand Master, Honorary Grand Master: All of the above plus either a lot more experience points or deep involvement within BJCP