This should work just fine.
<?
$f_name = $_POST[f_name];
$l_name = $_POST[l_name];
$phone = $_POST[phone];
$email = $_POST[email];
$additional = $_POST[additional];
$message = "Name: $f_name $l_name\r\n
Phone: $phone\r\n
";
$headers = "From: $email\n";
ini_set(sendmail_from, $email);
mail('mail@yourdomain.com','subject',$message, $headers);
?>
This is of course assuming that there is a form to fill out beforehand that uses the post method.
To help you out here the last line of code,
mail('mail@yourdomain.com','subject',$message, $headers); The email address is the email address to where it is being sent, you can change this to become a variable dependant on the prior form as well. The subject can also be replaced with whatever you want it to say, or also be a variable.
I hope this helps
Mike