New on his blog Phil Sturgeon has a post about the social integration package PHP has been dying for - NinjAuth. It has hooks for OAuth and OAuth2 connections and makes it simple to use them completely abstracted.
In the past I have never needed to implement oAuth into a PHP project. I have done it in Rails and boy it was easy thanks to OmniAuth. OmniAuth abstracts away so much of the grunt work that it takes about 5 minutes to add a new social network to your site, and 4 of those minutes are spent signing up for the API keys. What options do we have in the world of PHP? A bunch of screwy hacks or provider specific classes like TwitterOAuth. I don't want to hunt down 20 libraries with different methods, I want to get a key, bang it in and go to the pub. Well, now I can!
The fuel-oauth and fuel-oauth2 packages to drive its backend. He includes a code snippet showing how to configure the providers (complete with keys needed for auth) including Facebook, Flickr, GitHub, YouTube and - of course - Twitter. You can grab the latest version of this library from Phil's github account.