Log in anywhere with a single user name and password - OpenID!

What is OpenID?

OpenID is a decentralized single sign-on system. Using OpenID-enabled sites, web users do not need to remember traditional authentication tokens such as username and password. Instead, they only need to be previously registered on a website with an OpenID "identity provider" (IdP). Since OpenID is decentralized, any website can employ OpenID software as a way for users to sign in; OpenID solves the problem without relying on any centralized website to confirm digital identity.

How do I get an OpenID?

Surprise! You may already have one. If you use any of the following services, you already have your own OpenID:

AOL
openid.aol.com/screenname
LiveDoor
profile.livedoor.com/username
LiveJournal
username.livejournal.com
Orange (France Telecom)
http://openid.orange.fr/
SmugMug
username.smugmug.com
Technorati
technorati.com/people/technorati/username
Vox
member.vox.com
WordPress.com
username.wordpress.com

More:
http://en.wikipedia.org/wiki/OpenID
http://openid.net/
http://wiki.openid.net/OpenIDServers