I would like to let new users register with a Twitter OAuth for new' signups' to my project so not really wishing for Facebook implementation as yet. There seems to be a range of subjects & options via Drupal.org etc, but I'm simply looking for a quick and easy 'out of the box' solution to getting this going without having to waste lots of time trying to figure out which route to go. I already have a Twitter account so just need a pointer to best 'free' option geared towards Twitter for signup purposes to my projects. Thanks.
You can look into HybridAuth Social Login
This module integrates HybridAuth library into Drupal and allows your users to login and register using:
Facebook Twitter Google LinkedIn Foursquare Yahoo Windows Live MySpace AOL OpenID Github, LastFM, Vimeo, Disqus, Instagram, Viadeo, Identica, Tumblr, Goodreads, QQ, Sina, Murmur, Pixnet, Plurk, Skyrock, 500px, Vkontakte, Mail.ru, Yandex, Odnoklassniki, Twitch.tv, Steam and more
You can select which all social logins you want to enable. So if you are just looking for twitter you can enable that alone.