Para conhecer o protocolo OpenID:
OpenID : How’s it work? (http://openid.net/about.bml)
OpenID : authentication protocol flow diagram (http://openid.net/pres/protocolflow-1.1.png)
OpenIDEnabled : OpenID Protocol (http://www.openidenabled.com/openid/openid-protocol)
OpenIDEnabled : How Does it Work? (http://www.openidenabled.com/openid/about-openid)
e claro…
OpenID na Wikipedia (http://en.wikipedia.org/wiki/OpenID)
