Just stumbled on this item by Gonzalo Ayuso.
What caught my eye was the three words - PHP, websockets, nodejs.
Very interesting article complete with code. This will allow you to take a peek on how these three work together.
A nice read and very informative. If you got time, try the code out and build a real-world, working project out of it.
Real-time PHP site monitor using websockets and node.js