I have adapted the GAEMA code to allow my applications to authenticate with Google, Facebook, and/or Twitter. Though lightly tested, I believe this to work with GAE and in a "normal" web2py install.
Check out the details here: http://www.web2pyslices.com/main/slices/take_slice/77 Happy Authenticating! Christian -- Subscription settings: http://groups.google.com/group/web2py/subscribe?hl=en
