Well, you CAN do it that way, or you can just build one template up and leave the center blank for PHP included content. Its all rather hard to explain, so try looking at a template of mine over at
http://biorust.com/images/gallery/te...altemplate.zip for a practical example.
Oh, and the tutorial I made on Imageready is over at
http://biorust.com/index.php?page=tu...etail&tutid=23