Check out HTML::Template. It is a HTML templating package that I've used and been quite happy with.

If you really want to make your own templating system check out HTML::Parser. In it is a subclass called HTML::TokeParser (if I remember correctly) that will cleanly separate all the HTML tags so can just iterate over them with a foreach loop and not have to worry about spacing and the like.

Regex's to match HTML type tags can be pretty tricky. I'd be tempted to go with a pre-built package that already works correctly.

/\/\averick