Here is the awards and ranks guide for BF2:

The Unofficial Battlefield 2 Awards and Ranks Guide

I apologize if this link has already been posted earlier, but I was curious to know how to "level up" so I went searching...

I found the enlisted rank system to be very interesting. If you are not familiar with the Marine Corps ranking system let me explain.
In BF2 they have Master Sergeant or First Sergeant at level 8, and Master Gunnery Sergeant or Sergeant Major at level 9.
First Sergeant and Sergeant Major are considered administrative ranks, which why you have Company First Sergeants and Battalion Sergeant Majors.
Master Sergeant and Master Gunnery Sergeants are more technical ranks for running repair shops for instance.

What really blew me away was they have a Sergeant Major of the Corps, which is what they have in the Marines. In fact every branch of service has one, this rank belongs to the most senior enlisted person in that branch of service and that person gets to where a special insignia of rank that denotes such…
Wonder how you earn that one in the game??

Anyway, I know I caught AK late in the BF2 game, but I am really starting to enjoy this…