The Amazon Web Services PHP Development blog has a new post from Jeremy Lindblom showing you how you can receive inbound SNS messages via a webhook on your application.
Amazon Simple Notification Service (Amazon SNS) is a fast, fully-managed, push messaging service. Amazon SNS can deliver messages to email, mobile devices, Amazon SQS queues, and HTTP/HTTPS endpoints. [...] Though you can certainly subscribe your email address to receive SNS messages from service events like these, your inbox would fill up rather quickly. There is great power, however, in being able to subscribe an HTTP/HTTPS endpoint to receive the messages. This allows you to program webhooks for your applications to easily respond to various events.
Using the AWS SDK for PHP you can set up a listening script that can receive the message and handle subscription confirmations, message signature validation and handling the notifications.