?id=1 not working

I'm a php newbie and following one of the tutorials I got stuck with the following:

when submitting the following to my web server:
http:\mywebserver\test.php?id=1

and test.php contains:

<? php
if($id) {
something happens
}else {
something else happens
}
?>

then the else part always executes and the server returns with the "Notice: Undefined variable: id " error. (I have error reporting set to E_All)

if I try echoing the id varable I also get the undefined variable error.

what am I doing wrong?

There's been some recent changes to the way php references passed variables, for example
<? php
if(isset($_GET['id'])) {
something happens
}else {
something else happens
}
?>
see:
http://www.php.net/manual/en/language.variables.predefined.php

parse_url into variables...

thanks !