how to send html e-mails with php

This is a simple script for sending an html formatted e-mail:

$subject = "My Subject";

$headers = "From: paolo@pizzolongo.com\r\n";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";

$message = <<< EOT
< html >
< head >
< style >
body{background-color:#eee;margin:0;padding:0;border:0;}
h1{background-color:black;color:white;border-bottom:2px solid red;
font-size:16px; font-family:Arial;height:30px;line-height:30px;
text-indent:10px;vertical-align:middle;}
p{font-size:13px;font-family:Arial;line-height:1.2em;}


< body >
< h1 >Example Text< /h1 >
 

Hello,
this is a little text example.
Paolo's web site
regards


EOT;

mail($send_to,$subject,$message,$headers);