Social Login is a WordPress plugin by ClaudeSchlesser that allows your
visitors to comment, login and register with social networks like Twitter, Facebook, LinkedIn, Hyves, Вконтакте, Google or Yahoo.
Choose where to add the social login feature:
On the comment formular
On the login page
On the registration page
Optionally add the widget:
A login widget that you can easily attach to your sidebar is provided
Select the Social Networks/Providers:
Facebook
Twitter
Google
LinkedIn
Yahoo
OpenID
WordPress.com
Hyves
VKontakte (Вконтакте)
Download and info: http://wordpress.org/extend/plugins/oa-social-login/