On the BinaryTides.com site there's a recent tutorial showing you how to effectively use sockets in your PHP applications, complete with incoming and outgoing examples.

This is a quick guide/tutorial to learning socket programming in php. Socket programming php is very similar to C. Most functions are similar in names, parameters and output. However unlike C, socket programs written in php would run the same way on any os that has php installed. So the code does not need any platform specific changes (mostly).

They start with the basics - creating a socket, connecting to a server and sending out information over the connection. They also include the code examples showing how to pull in data from the socket. Their example socket is set up to be a simplistic web server, returning data according to the standards for a normal GET request. They make a mini-server out of it, getting to to accept requests on a bound socket.