render :kml

kml is an xml format used by Google Maps for specifying a map and
markers and other things in the GMap. I have a model Carrier which
has_many :addresses. Each Address has the standard fields (address1,
address2, city, state, zip) as well as geocode latitude and longitude
strings. Is it trivial to render a Carrier's addresses in a kml
file? I hope I can include something like this in the carrier

def render_kml(carrier)
  @carrier = Carrier.find(carrier)
  render :kml => @carrier.addresses

But I know that I will have to massage the address fields into the kml
xml schema.

Does anyone know any tutorials for rendering collections into xml

Thanks in advance!