I did two year with JET and I really enjoyed it.
About the interview. They don't expect people to be Japanese experts. They just want to see that you have a genuine interest in Japan. They also want to see that you are a fairly personable individual because you will have to interact with Japanese staff and students daily.
In the interview I was asked why I am interested in going to Japan, what areas of Japanese culture I was interested in etc. The Japanese embassy member who was in the panel asked me how I would rexplain the difference in England and Scotland to Japanese students (I had the interview in Edinburgh). I think (the interview was 5 years ago now) I was asked about disiplining a naughty student also.
I think the main thing for the interview it to be confident and display a genuine interest in Japan. Don't fake knowledge of Japan you don't have because they are the experts. They don't expect it either, they are looking for suitable people to become Japan experts.
Hope this helps. Good luck with your interview if you havent already had it.
Last edited by dan
on 5 Apr 2009 8:24, edited 1 time in total. Reason: Advertising website unrelated to ELT