OpenID, the "decentralized standard for user authentication and access control" has a nice feature whereby you can use your own domain as your OpenID login.

Basically you put a few lines of HTML in your <head> tag, and any OpenID supporting basically treats it as a redirect.

I have a Verisign PIP OpenID account, to login to various sites (such as the Stackoverflow "family" of sites), but I can use my own domain (dbrweb.co.uk) as a login.. I could run my own OpenID "endpoint", but this is much simpler, and more secure (as Versign will do a better job than I could)