On the PHP::Impact blog Federico offers a brief tutorial on creating a simple web service client with the help of the Zend Framework.

The Zend Framework puts heavy emphasis on Web services. This is a good thing, considering the amount of Web services out there that can help lower costs and increase the value of your site. [...] In this example, I’ll develop a Web services client to Digg, a real-world Web services provider.

He steps through the process - finding the provider information, locating their endpoints, setting up query string interfaces, making code to handle the responses and, finally, making the actual client as a Zend_Rest_Client interface.

Dave Marshall has a (very) quick post on tying together your Zend Framework application with the Twitter API.

Zend_Service_Twitter looks like it will be fairly comprehensive, but it's not in the core yet and is probably a little overkill for my simple use case. I then had a look at Zend_Rest_Client, which seemed to confuse me. I couldn't actually get it to add the parameters I wanted to the call, I guess it’s better for interacting with Zend_Rest_Server or fully restful APIs.

He opts for the Zend_Http_Client component and includes the simple fifteen line script to make the connection and post a new update.