Here are a couple of articles I wrote describing a couple of handy
helpers for dealing with polymorphic objects.
These helpers allow you to generate urls and render partials on objects
without knowing what class they are ahead of time.
http://www.sciwerks.com/blog/2006/05/24/polymorphic-urls/
http://www.sciwerks.com/blog/2006/05/24/polymorphic-partials/
Hopefully you will find them useful.
_Kevin