Rails - Mar 2005 - Location of method

I''m a little confused as to where I should put a permalink method
for my blog. It needs to available in the controller (think trackbacks
and APIs) as well as the templates.

The problem is that if I define the method in the controller, I don''t
have access to link_to, which is an AV method. If I define the 
method as a helper, it isn''t available in the controller.

The method should look something like this:

   def permalink (text, entry)
     link_to text, :slug => entry.slug ... etc.
   end

How do I solve this particular catch-22?

Thanks for any insights.

-- 
Regards,
Stian Grytøyr