function loadPageFirst() {
    // get the actual category
    $actualCategory = get_category( get_query_var('cat') );
    // get the page with the same slug
    $matchingPage = get_page_by_path( $actualCategory->slug );

    // If no match, load the normal listing template and exit (edit if you are using a custom listing template, eg. category.php)
    if (!$matchingPage) {
        include( get_template_directory() . '/archive.php');
        die();
    }

    // Make a new query with the page's ID and load the page template
    global $post; $post->ID = $matchingPage->ID;
    query_posts( 'page_id=' . $matchingPage->ID );
    include( get_template_directory() . '/page.php');
    die();
}
add_filter( 'category_template', 'loadPageFirst' );