1123981:There are several types of certification. Rules knowledge, tournament organizer, player management, and I think one or two more. For judgeing I believe all you really need is rules knowledge, but having the others wouldn't hurt.
Actually you don't even need a Rules Knowledge certification to Judge a tournament. Obviously the people in charge would prefer people to have some sort of certification and whatnot, but it's not required in order to Judge.
There's also Scorekeeping and Demo Team certification tests.
Magneto:We are the future, Charles; not them.
Player Management: Level 2
Rules Knowledge - VS System: Level 1
Rules Knowledge - World of Warcraft: Level 2
Rules Knowledge - Yu-Gi-Oh!: Level 2
Tournament Organizer: Level 1