You might want to try this out. It is a recent blank Web2py application with a plugin that gives you a language changing button. At the moment it requires some manual intervention to add it to a site. ( need to edit layout.html and perhaps some other stuff ).
Install instructions are included in the plugins about file It is a development version but I have had no issues with it. project source http://code.google.com/p/uc-language-dev/ Site using the menu chrissteel.com
