This is my signin Form:

<FORM ACTION="authenticate.php" METHOD="get">
USERNAME: <INPUT NAME="Username" TYPE="text" ID="Username"><BR><BR>
PASSWORD: <INPUT NAME="Password" TYPE="text" ID="Password"><BR><BR>
<INPUT NAME="Login" TYPE="submit">
</FORM>

so how would i declare those two variables in php script, like this?

$Username =$_POST['Username'];
$Password =$_POST['Password'];


Thanks
Robert