I pulled up the carpet and pad and then set the circular saw to 5/8ths and cut some seems in the particle board to make it easier to pry up. I then started in the corner with a prybar and flat shovel and ripped all that nasty stuff up.
It actually pulled up pretty easily. Heres a picture with the particle board removed and all the nails pulled. The subfloor is 1/2 of 5/8ths plywood and its not nailed down very well which explains why my floor always felt bouncy and make so much noise. I'm going to have to secure this layer with a few pounds of screws prior to laying anything else on top of it.