Recently, Twitter rolled out a great new feature on their site – lists. You can now create and compile a list of twitter users and make it easier for others to follow all at once.
Also, at the same time, they expanded their API to include list management functionality. This allows us to use these new tools to create a widget that flips lists the other way around – a fan page you can put in your sidebar, that allows your visitors to fill in their twitter name and join a specially crafted fan list in your twitter account.
So download the example files and lets start coding!
http://tutorialzine.com/2009/11/twitter-list-ajax-fanpage/