What's the proper way to create a new page option? I want to show comments of a node on a separate page instead of on the node page. 
Since this is just a "comment archive" and not active I would like a simple solution without a big module or a lot of code.

I can "hack" the node--mytype.tpl.php page to show comments when the "?archive" is in the URI:

    $uri =  check_plain($_SERVER['REQUEST_URI']);
    if (strpos($uri, '?archive') &gt; 0){
        print render($content['comments']); 
    }
    else {
        print l('View Comment Archive', $uri.'?archive');
    }


This works fine, even with the comment pager. I'm curious what the "proper" way in Drupal would look like.
The easiest way to to use Views.

You can create a view over Comments, or you can make a view over Content and then add a relationship to the node's comments.  There are advantages and disadvantages to both.  You just need to play with them to see what works best for your situation.  

With either method, you can use any of the normal means for adding a view to you site.