If you're looking for a free alternative, check out SSI from AddThis: http://www.addthis.com/labs/social-sign-in#.UIBqXRj0CnM http://www.addthis.com/labs/socia

If you're looking for a free alternative, check out SSI from AddThis: http://www.addthis.com/labs/social-sign-in#.UIBqXRj0CnM http://www.addthis.com/labs/social-sign-in#.UIBqXRj0CnM You will have to store your user info yourself, but it does take care of oAuth for you. Full disclosure: I work for AddThis and worked on this feature.