[Help with Error]

Hello.

I am fairly new to PHP, and am struggling over a error. Any help would be kindly appriciated.

Error:

[code]Notice: Undefined index: id in c:\home\********\public_html\index.php on line 3[/code]

Code

[code]<?php
include("/home/********/public_html/modules/template-top.php");
$page= $_GET['id'];
if(file_exists("/home/********/public_html/content/".$page.".php"))
{
include("/home/********/public_html/content/".$page.".php");
}
else
{
include("/home/********/public_html/modules/news.php");
}
include("/home/********/public_html/modules/template-bottom.php");
?>[/code]

If you can help, I would be most pleased.

Thanks, Stobbo.