OAuth 2.0 is the next evolution of the OAuth protocol which was originally created in late 2006. OAuth 2.0 focuses on client developer simplicity while providing specific authorization flows for web applications, desktop applications, mobile phones, and living room devices. This specification is being developed within the IETF OAuth WG and is based on the OAuth WRAP proposal.

Questions, suggestions and protocol changes should be discussed on the mailing list.

Reading the spec

The latest version of the spec is can be found at http://tools.ietf.org/html/draft-ietf-oauth-v2.

Implementations

Servers

• Facebook's Graph API (draft 10) - http://developers.facebook.com/docs/authentication/ (see http://www.sociallipstick.com/?p=239)
• Salesforce (draft 10) - http://www.ietf.org/mail-archive/web/oauth/current/msg04391.html 
• Gowalla (draft 8) - http://gowalla.com/api/docs/oauth
• 37Signals (draft 5) - http://groups.google.com/group/37signals-api/browse_thread/thread/86b0da52134c1b7e
• GitHub - http://github.com/blog/656-github-oauth2-support 
• Ruby oauth2-server (draft 0) - http://github.com/aflatter/oauth2-ruby

Clients

• Cocoa - http://github.com/leebyron/cocoa-oauth2
• iPhone and iPad - http://github.com/lukeredpath/LROAuth2Client
• Ruby Gem - http://github.com/intridea/oauth2
• Ruby oauth2-core - http://github.com/aflatter/oauth2-ruby
• PHP (draft 9) - http://code.google.com/p/oauth2-php/
• Python - http://github.com/dgouldin/python-oauth2