RoutedApp is a project mainly written in ..., it's free.
A demo using Ext.ux.app.RoutedApplication with Ext.ux.Router
== Sample ExtJS Application using Router
Clone this repo into your server's "public/javascripts" directory.
Move the supplied "index.html.example" file to your server's /public/index.html
Copy ExtJS4 library to your server's "public/javascripts" directory
Adjust script-urls as necessary to suit your environment. ExtJS library is poinint to ext-4.0.2a