This project builds off of the Drupal Social Initiative.
Social Auth Twitter allows users to register and login to your Drupal site with their Twitter account. It is based on Social Auth and Social API projects
This module adds a path user/login/twitter which redirects the user to Twitter Accounts for authentication.
After Twitter API has returned the user to your site, the module compares the email address provided by Twitter. If your site already has an account with the same email address, user is logged in. If not, a new user account is created.