I had a need for social sign in recently in a project that I needed to complete in a weekend. Rather than build something using Facebook/Google/Twitter/etc. APIs I used oneall. A small amount of javascript and a backend call later and I have pretty good social sign in integration with a bunch of providers. Your control over the look of the div they supply is limited (at least in the free version) but the integration is good. Recommended.
Adventures in Computer Programming – bakert@gmail.com