best practices for calling a web service (like geocode)

Guys,

I have a Customer class which creates an instance of an Address class, and the user can then go into the show method of the Customer class and associate other addresses with that Customer (sites). As soon as an Address instance is created, I want to call geocoding to get the latitude and longitude of that address so that I can later render a map of all the sites. now, I suspect that a call to the geocoding url synchronously would be a bad thing:

def create   @address = Address.new(params[:address])   ... assign other @address parameters   ...   create a geocoding instance   call geocoding, passing in address string, getting back a lat and a long <--- wait wait wait wait   @address.latitude = lat; @address.long = long end

What's the best practice for doing something like this in ruby/rails?

TIA,