multiple-login

Is there a PHP plugin or an open project offering a simple login/connection system to most of the major sign in providers simply by providing an API key then storing the linked account information in MySQL? Or is there a system that can be extended to include various other login providers as they become available? Google Account / gmail / blogger Yahoo! OpenId / ymail / Flickr Facebook Connect Twitter OpenId MyOpenId MediaWiki Wordpress OpenID MySpaceID AOL / AIM Windows Live It is not a plugin but something you add to your site. However, take a look at Dope OpenId , it is rather easy to use

Okay, I got a website where you can register yourself and login. You can also login with your facebook, twitter or linkedin account. It is important that users only have one account registered. So somehow, I want to merge the accounts of users if they use different methods to login. What is the best solution to solve this? For instance, the user logs in with his Facebook account. I use the data to register an account for him automatically. Should I sent an e-mail with an username and password of our website? (If this is okay with the policy of Facebook). Should I give them a second screen