A few days ago, techPortal published my tutorial Create a RESTful API with Apigility.
Apigility was announced at ZendCon US in October 2013 and I think that it looks like a useful tool for creating APIs. I particularly like that versioning is built in from the start and that it handles content negotiation.
If you want to learn about Apigility, then have a read. The source code is available on GitHub.