[form security]

Help! I have a simple form on my website--host shut it down because they said it is being used by spammers to send email. My code:

[code]if (isset($_POST['Name'])) {
$n = $_POST['Name'];
$em = $_POST['Email'];
// Configuration Settings
$SendTo =      "xxx@xxx.com";
$SubjectLine = "xxx resumé";
//$from = "From: $visitormail \r\n";
$headers .= "From: ";
$headers .= $n;
$headers .= "<";
$headers .= $em;
$headers .= ">\r\n";


$Divider =     "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~";

// Build Message Body from Web Form Input
$MsgBody = @gethostbyaddr($REMOTE_ADDR) . "\n$Divider\n";
?> <?php

foreach ($_POST as $Field => $Value)
   $MsgBody .= "$Field: $Value\n";
   $MsgBody .= $Divider . "\n" . $HTTP_USER_AGENT . "\n";
$MsgBody = htmlspecialchars($MsgBody);  //make content safe

// Send E-Mail
mail($SendTo, $SubjectLine, $MsgBody, $headers);[/code]

Will someone please tell me how to change this so it is safe?

Thanks so much!