PaulS:
I have the example Sketch working so it shows the Analogue port data.
That would be an Arduino-as-server or Arduino-as-client sketch?
How do I write a simple sketch that works with my website rather than Twitter to interface with my Arduino and ethernet shield? Is it RSS related, so a simple .xml file?
Typically, this is done with the Arduino as server. It matters not where you connect from, then.
You appear to want the Arduino to contact your web server for information (should the light be on or off). Why is that?
Is it RSS related, so a simple .xml file?
No.
Alternately, I have a Micro SD card plugged into the Ethernet shield it's 8gb in size, is there a way to store HTML, XML and PHP documents on it and just call them when they are needed?
You call functions. You read text files.
Sending data that contains php code doesn't make sense. The PHP code is supposed to be executed on the server, so it alters the data that is sent. You can't run PHP on an Arduino.
The Sketch is just the sample one provided by with the IDE.
I do want the Arduino to contact my website so it can be updated from it, like Twitter is used.
If I call functions (text files) how?
Is RSS now xml? and isn't twitter RSS?
If PHP is server side that would work for an online Web-server to do some post processing right? Why rely strictly on the Arduino?
Can you help me with this or no?