The FreeSitemapGenerator.com webmater tool creates a sitemap as defined by Google for your site. Simply enter the url of your website(s) – and the online generator will create the necessary files for you. Free accounts can scan for up-to 5000 pages – which can be increased to 25,000 by upgrading to a paid premium account.
An important thing to note is that FreeSitemapGenerator.com does not create HTML sitemaps – only compressed XML formats. These are perfectly acceptable by Google, however if you want something your visitors can also browse – I would recommend trying XML-Sitemaps.com.