Google-viewer is a project mainly written in Ruby, it's free.
Easy to use Google Docs viewer url generator
== GoogleView
Simple class for generating Google Viewer urls.
== Usage
require 'google-viewer'
g = Google::GoogleViewer.new('http://example.com/example.pdf') g.viewer_url # http://docs.google.com/viewer?url=http%3A%2F%2Fexample.com%2Fexample.pdf g.url # http://example.com/example.pdf