To create your sitemap before submitting it to Google, you can use Arne Brachhold’s wordpress plugin. The plugin will create a Google sitemaps compliant XML-Sitemap of your WordPress blog. It supports all of the WordPress generated pages as well as custom ones. Everytime you edit or create a post, your sitemap is updated and all major search engines that support the sitemap protocol, like ASK.com, Google, MSN Search and YAHOO, are notified about the update.
You can download the plugin at http://www.arnebrachhold.de/projects/wordpress-plugins/google-xml-sitemaps-generator/
