Add JS and CSS files in *.tpl.php in Drupal6

function yourtheme_preprocess_node(&$variables) {
if ($your_condition) {
drupal_add_css(path_to_theme(). "/filename.css", "theme");
$variables['styles'] = drupal_get_css();

drupal_add_js(file_directory_path() .'/javascript.js', 'inline');
$vars['scripts'] = drupal_get_js();
}
}