In order to become a moderator, you have to apply for a job at Sony and be willing to move out to their offices in California.
We had a thread similar to this the other day, actually. Case and point, if you want to become a mod, you need to plan out having a job with Sony. Moderating these forums is a full time job and Sony takes the idea of a forum moderator very seriously.
This was the similar thread I mentioned. It was actually on the first page.