Using mail() to send a simple email:
<?php
// The message
$message = "Line 1\nLine 2\nLine 3";
// In case any of our lines are larger than 70 characters, we should use wordwrap()
$message = wordwrap($message, 70);
// Send
mail('caffinated@example.com', 'My Subject', $message);
?>
Sending mail with extra headers:
<?php
$to     = 'nobody@example.com';
$subject = 'the subject';
$message = 'hello';
$headers = 'From: webmaster@example.com' . "\r\n" .
  'Reply-To: webmaster@example.com' . "\r\n" .
  'X-Mailer: PHP/' . phpversion();
mail($to, $subject, $message, $headers);
?>
