I have created an simple Ruby Wrapper API for Zillow API. It does all the webservice call for you. It will convert the xml into an ruby hash/array format. The api is open source and hosted in http://rubyforge.org/projects/rillow/ . It is a very simple api and can use most more improvement in the future. However, it will save a couple hours of your time if you need to write something like that in Ruby.
Rillow - An Ruby Wrapper api to Zillow API