If you want to do it yourself, then do something like this
$to = "someone@somnewhere.net";
$message = "Your Message:\r\n\r\n" .
"FIELD 1: " . $field1 . "\r\n" .
...... etc
"FIELD B:" . $fieldn . "\r\n";
$subject = "Your subject";
mail($to, $subject, $message,
"From: [email]formsubmit@yourdomain.com[/email]\r\n" .
"Reply-To: DO NOT REPLY Incoming only\r\n")
or die("Temporary Network Failure. Please try again later.");