PHP: simple contact form

gistfile1

<?php 
/**
 * @author Mad Jack
 * simple contact form
 */
if (strtoupper($_SERVER['REQUEST_METHOD'])=="POST") {
	$fullname = $_POST['fullname'];
	$email = $_POST['email'];
	$phone = $_POST['phone'];
	$comment = $_POST['message'];

	$mailSubject = "Look11 Website Contact Form";
	$headers = "From: " . '' . "
";
	$headers .= "Reply-To: ". '' . "
";
	$headers .= "MIME-Version: 1.0
";
	$headers .= "Content-Type: text/html; charset=ISO-8859-1
";
	
	$message = 'FROM: ' . $fullname . '<br>';
	$message .= 'EMAIL: ' . $email . '<br>';
	$message .= 'PHONE: ' . $phone . '<br>';
	$message .= 'MESSAGE: ' . $comment . '<br>';
	
	mail('', $mailSubject, $message, $headers);
}


/*CSS*/
/* CONTACT FORM STYLING */

.contactForm {
	clear: left;
	margin-top: 15px;
}

.contactForm input[type=text] {
	height: 20px;
	width: 400px;
}

.contactForm input[type=text], .contactForm textarea {
	background: white;
	border: none;
	padding: 3px;
	font-size: 12px;
	margin: 3px 0 3px 0;
}

.contactForm textarea {
	width: 400px;
	height: 100px;
}

.sendBtn {
	cursor: pointer;
	height: 21px;
	float: left;
	line-height: 21px;
	color: white;
	font-size: 10px;
	padding: 0 3px 0 3px;
	background: #e30043;
	margin-top: 10px;
}

.sendBtn img {
	float: right;
}


<form method="post" action="/contact/" id="contactForm" name="contactForm">
					<p class="lightgrey">Name:</p><input type="text" name="fullname"></input><br /><br />
					<p class="lightgrey">Email Address:</p><input type="text" name="email"></input><br /><br />
					<p class="lightgrey">Phone Number:</p><input type="text" name="phone"></input><br /><br />
					<p class="lightgrey">Message:</p><textarea name="message"></textarea><br />
				</form>
				<div class="sendBtn" onclick="checkFields();">SEND<img src='/images/searchBtn.gif' /></div>

 ?>