Right now you can't, we will open up the Staff Applications in about a week.
If you want to become a Staff member I recommend you act mature, stay active and committed to the community, hang out on the website a lot, have fun, play ZAM obviously.
One thing that will obviously make you a lot more attractive as an Admin or Staff Member is if you have a skill no one has so far so you can help us, mainly I'm thinking about programming or website development, but could be something else as well.
Good luck.