Rails: Database records with custom route...?

Question

I have a model, target, that holds a number of records that are timestamped. On the corresponding controller, I list the months of those records by doing the following:

In models/target.rb

def month
   self.recorded_on.strftime('%B')
end

In controllers/targets_controller.rb

@records = Target.find :all

In views/targets/index.html.haml

%ul
  - @records.group_by(&:month).sort.each do |month, data|
    %li= link_to month, ''

That all works great for listing the available months for the records that I have. Next, I want to be able to click on the month and get a report of all the records for that month, at the following path generated with year and the month: /targets/2009/04

How would I do this?