Restful routing help

Ok so I am making a directory, the flow of the directory should be
category to state to county to city to zip. I cant get it to work so
that when you click on a certain category it links to you all the
states it has. so far this is what i have.

routes.rb

map.resources :categories, :has_many => :states
map.resources :states, :has_many => :counties

So they start off in the show action of the categories controller
which is

categories_controller.rb

def show
@categories = Category.find(:all)
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => @categories }
end
end

here is my show view for categories

show.html.erb

Listing categories

<% for category in @categories %> <% end %>
<%= link_to category.title, state_path(@state) %>

here is my states controller

states_controller.rb

def index
@states = @category.states
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => @states }
end
end

and here is my index view for states

index.html.erb

Listing States

<% for states in @categories.states %> <% end %>
<%= link_to state.title, county_path(@county)%>

now I can get to the categories view and see all the categories but
when I click on a specific category to go to show all the states it
has it throws a error. Any help would be greatly appreciated, thnks
in advance.

Does anyone know? or can point me in the right direction?