“On his blog Ian Selby wrote a tutorial”:http://www.gen-x-design.com/archives/create-a-rest-api-with-php/ that takes you from ground up in building a REST API using PHP. It explains what REST is, why you would consider it over SOAP, and then step by step takes you through constructing the code to make it all happen.
bq. One of the latest (sort of) crazes sweeping the net is APIs, more specifically those that leverage REST. It’s really no surprise either, as consuming REST APIs is so incredibly easy, in any language. It’s also incredibly easy to create them as you essentially use nothing more than an HTTP spec that has existed for ages. One of the few things that I give Rails credit for is its well thought-out REST support, both for providing and consuming these APIs (as its been explained by all the Rails fanboys I work with).