im sorry...im running windows 7
Well, you will be, then. There is a flaw in the Windows OS that prevents PHP from reading serial data. It can write to the serial port, but not read from it.
So, while you might eventually figure out how to tell the Arduino that you want to know something that it knows, you will not be able to read its response. Not using PHP, anyway.
You could get a copy of Visual C# from Microsoft (they actually give it away), and write an application that communicates with the serial port. You can also create HTTP GET, PUT, and POST requests and send them off to be acted upon. Of course, you can then read any reply that is returned.
The help that comes with Visual C# is abysmally difficult to navigate, but, it does include a search field and does include examples. You could possibly copy an entire example and be talking to the Arduino and twitting in less than an hour. After you download and install the software, that is.