Problem with forms in Rails 2

I built an app 2 years ago with version 1. I'm now using version 2.0.2
and I've noticed that forms have changed. I've a CRUD controller and my
create and update methods use params[:id] but the id is not in the
form's post data anymore. It used to put the id in the action url but
now it doesn't. My form template likes like this:

<% form_for(:point, :url=>{:action => 'update'}) do |point| %>
...
<% end %>

and my controller method:

def update
   @point = Point.find(params[:id])
   saved=@point.update_attributes(params[:point])
   ...
end

Any ideas?