How would you design and implement OpenID components?
(Was \"How does OpenId work\")
I realize this question is somewhat of a duplicate, and yes
Jeff has a great article on OpenID where he shares his experiences:
OpenID: Does The World Really Need Yet Another Username and Password?
There are some links to tutorials on the official OpenID site:
http://openid.net/developers/
You can get a nice login-control for OpenID (which also is used here on stackoverflow) here:
http://www.idselector.com/