Code Question: OpenID, Gmail, Facebook, Yahoo login for Wordpress

I am looking for a way to allow users from different sites

to login with their respective username/id.

An example can be seen on this page

Is there something like this for free for wordpress?

From web app ilhan

For self-hosted WordPress or WordPress.com? (The former is really off-topic for this site.)

Self-hosted, there is this plugin, which allows visitors to use OpenID to identify themselves to register, log in, and leave comments.

For WordPress.com, you can use your blog as an OpenID provider for other sites. You can see the sites where you use this under Settings | OpenID. There's not a way to use OpenID to log in, however.

phwd : It is mostly like the self hosted WP he is talking about.I think the OP means a plugin where one can login into page restricted sites. Such as the one he gives http://codecanyon.k42b3.com/openid/ shows a message : You are not logged in click here to authenticate.

ilhan : I mean self hosted WP.

From Al Everett
Word press has an openid plugin. I am not sure if it works with the other login services.

This plugin can do also other services like

Quickly register and login users with their existing accounts from Facebook, Twitter, Google, Yahoo!, LinkedIn, Windows Live, MySpace, AOL or OpenID

From txwikinger
Another good plugin is http://wordpress.org/extend/plugins/rpx/

From Brian Kissel

Code Question