How to make index.php into a WordPress Page Template?

Simply, I want to create a duplicate index.php in my blog but as a page template. I don’t need any special post order or anything like that.

How do I use query_posts in a page template file so that the index.php and the template is the same?

I tried using:

<?php query_posts(); ?>
<?php query_posts($query_string); ?>

but they didn’t work