<?php
/*
Plugin Name: Atom Feed Selector
Plugin URI: http://wordpress.org/#
Description: This plugin replaces the default wp_feed_selector filter with
one that choses the Atom 1.0 feed.
Author: Sam Ruby
Version: 0.1
Author URI: http://intertwingly.net/
*/

function atom_feed_selector($attr = 'name') {
        switch ( $attr ) :
                case 'mime_type' :
                        return 'application/atom+xml';
                case 'display_name' :
                        return 'Atom 1.0';
                case 'short_name' :
                        return 'Atom';
                case 'long_name' :
                        return '<a href="http://www.atomenabled.org/">Atom</a>';
                default :
                        // must be 'rss2', 'rss', 'rdf', or 'atom'
                        return 'atom';
        endswitch;
}

remove_filter('feed_format', 'wp_feed_selector');
add_filter('feed_format', 'atom_feed_selector');

?>