trying to add a custom menu page to my wordpress theme

Solution:

add_action('admin_init', 'theme_options_init');
add_action('admin_menu', 'theme_options_add_page');

function theme_options_init() {
    register_setting('theme_options', 'mytheme_theme_options', 'theme_options_validate');
}

function theme_options_add_page() {
    $page = add_theme_page(__('Theme Options', 'mytheme' ), __('Theme Options', 'mytheme'), 'edit_theme_options', 'theme_options', 'theme_options_do_page');
    add_action('admin_print_styles-'.$page, 'theme_options_js');
}

function theme_options_js() {
    // whatever js you need...
    wp_enqueue_script('jquery-ui-core');
}

function theme_options_validate($input) {
    $input['sometextarea'] = wp_filter_post_kses($input['sometextarea']);
    return $input;
}

function theme_options_do_page() {

    if (!isset($_REQUEST['settings-updated'])) {
        $_REQUEST['settings-updated'] = false;
    }

    ?><div>

    your theme options page 

    </div><?php

}