theres no need to really make the html into php, you can mix the two up, heres how i usually do it
index.php
<?php include ("header.php"); ?>
regular html code of the index page can go here. if i want i can mix <?php echo "PHP"; ?> in with the html.<br /><br />
Then finally when I'm done I can...<br />
<?php include ("footer.php"); ?>