OpenID is a nice authentication method. You just register at any of the OpenID provider sites. I chose Symantec Personal Identity Portal because the company that works on data security can be trusted much more than Google or whatever else. Once registered, you can either use the OpenID URL they gave you on registration, or better, just pick an URL you control and put some delegation code there. This page is my OpenID page, for example. Since I own this domain, I can continue to use this URL forever, even if I have to change my OpenID provider someday (for example, because it is shut down or whatever).

Sergey A. Tachenov