Does the state your in have a test or something and if so is it hard?
Any MMA judges out there?
^^ ????
If the state you are in has recently regulated MMA and there are not alot of boxing judges, becoming a judge is probably attainable. I know a few judges here in SC, they had some MA experience and knew another judge, ref or commissioner and were able to get into judging. I doubt you can get in without connections in a state like NJ, NV or Cali since combat sports are more established 
It is easy to judge MMA until there is a close fight. Then it is really hard.
As far as getting certified, that varies from state to state. What State are you in, I can check?
TTT for judging.
I am a certified MMA judge. In order to get certified, I had to take a certification course and then "shadow" judge a live event. During the event, the trainer compared my dummy scorecards to the live scorecards. Whether my scores agreed with the other judges or not, I also had to verbally discuss why I scored a round the way I did and justify my score. I can tell you that on at least 2 fights, my scoring would have changed the outcome of a decision. After the event, the trainer beleieved that I judged the fights correctly using the correct criteria and signed off on my certification.
Now being certified and being licensed in a state are two different things. Currently, I am licensed for amateur MMA and I plan to apply for my pro license after I have 100 or so amateur fights under my belt.
Kirik - It is easy to judge MMA until there is a close fight. Then it is really hard.
As far as getting certified, that varies from state to state. What State are you in, I can check?
First sentence is very true. Somehow judges still manage to mess up some easy ones, but I've seen many rounds where I'm glad I'm not responsible for handing in a score. 
I guess first two sentences haha
In Iowa there are no official requirements for MMA judges...that being said, having a background training and/or competing in MMA is helpful. I have judged on several occasions...I have 8 ammy and one pro fight under my belt, and I also work as a ref from time to time. If MMA is regulated where you live, the best way to get info would be to contact the combative sports/boxing commission or whatever regulatory body oversees MMA. As far as the difficulty of being a judge; it's really not. Just keep in mind that it can be a thankless job (much like reffing). Sometimes, no matter what call you make or how you score a round, people will disagree with you, get pissed, etc. On the plus side, judges usually get cageside seating.
Kirik - It is easy to judge MMA until there is a close fight. Then it is really hard.