An open and decentralized identity system, designed "not to crumble if one company turns evil or goes out of business". Official site, with description, specifications, documentation, and resources.

Encyclopedia article, with description, technical details, adoption progress, and criticisms.

Secure OpenID provider. Includes background information and online signup.

Weblog article explaining how the technically minded can set up their own OpenID identity.

Provides resources for users and developers.

Uses client-side SSL certificates instead of passwords to provide secure OpenID authentication based on public-key encryption.

Provides free OpenID accounts. Includes terms of use and frequently asked questions.

News article by Phil Becker and Eric Norlin outlining the advantages of the system.

Provides a list of OpenID enabled sites, also includes a category for related software and online tools.

A bilingual OpenID provider with a particular focus on the Chinese market. Background information as well as online signup are available.