For Elaine - this would go in your functions.php. The is_category could be made more specific if you wanted, of course. One slightly irritating global needed. :)

Change Comment Title

add_filter( 'comment_form_defaults', 'dc_change_form_title');
function dc_change_form_title($arg) {
     $arg['title_reply'] = __('Please Comment');
     return $arg;
}

To get comments on a category page

add_action('genesis_after_endwhile', 'dc_cat_loopiness');
function dc_cat_loopiness() {
	if ( is_category() ) {
		global $withcomments;
		$withcomments = "1";
		comments_template();
	}
}