// TO ALPHABETIZE THE POSTS
function mw_change_post_order(){
    if ( is_archive() ){
        global $wp_query;
        $args = array_merge( $wp_query->query, array( 'orderby' => 'title','order' => 'ASC' ) );
        query_posts( $args );
    }
}
add_action('genesis_before_loop','mw_change_post_order');