hook_preprocess_page(): how to tell a views page?
views_get_page_view() finds out what, if any, page view is currently in use. If it returns NULL, then the current page is not a views' page.

But using drupal_add_js() and drupal_add_css() in a hook_preprocess_page() won't work as expected because the variable $script and $style variables have already been set by template_preprocess_page(). Views's template preprocessing (see Jeremy French's answer) is probably a better place to add your CSS and JavaScript.