New lines?

[New to VB 6]

I'm useing the code below to add people to my mailing list, however it will not automaticly make a new line for the new entry.
any ideas on how I can do that?

<?php
$text = implode(":", $_POST);
   $text += "\n";
$fp = fopen ("list.txt", "a+");
fwrite($fp, implode(":", $_POST));
fclose($fp); 
?>

<?php echo implode(":", $_POST);?>