Since no one else seems to take this question seriously.
Administrators are usually hired based on their behavior in game, on the forums etcetera. Admin Simen, Garry and Tom were all hired after working themselves up to Head Moderator from Junior Moderator (you can apply for junior moderator in the groups section of the User Control Panel).
However, in some occasions, they are hired due other reasons such as by actively searching outside of the community because of need (Seth and Joe), because or a particularly standing out application by an upstanding community member (Andrew), because of a strong community push (Milan) or because Michael simply noticed an individual who seems to have a strong will and a desire for change (Ilona).
If you wish to be an Admin yourself, I recommend getting to know the community well and acting as you feel an admin should ask. Then you could either take the route through the staff, or try talking to Michael and/or Ilona.
Hope that answers your query.