I had a lot of fun giving this talk for the virtual PHP user group, Nomad PHP. What I love about this group is that it's open to everyone, wherever and whoever you are. They hold events in varying timezones to reach as many people as possible - and if that still doesn't work for you, then you can always sign up to receive the video later.
This talk covers both concepts and code, walking through the real nuts and bolts of putting together both a frontend and backend, both built in PHP with Slim framework. It is accompanied by a GitHub repo of sample code and instructions on how to use OAuth to make the logging in step easy.
I'll also be giving this talk at a couple of other events this autumn, PHPNW and ZendCon