http://www.xml-sitemaps.com/

This tool lets you create sitemaps for different purposes like:

• Create an XML based sitemap which can be submitted to Google so that it can crawl your website in a better way.
• Create a Text based sitemap which can be submitted to Yahoo.
• Create a ROR based sitemap, which is an independent XML format for any search engine.
• Generate an HTML based site map which helps visitors to easily navigate on your website.

Depending on your requirements you can specify the optional parameters like frequency change for page, last modification date time values and priority. This free version indexes a maximum of 500 URL in a sitemap.

To create a sitemap first add a full website URL to field starting URL with desired optional parameters, then click start button which will crawl and index pages. The result details shows number of pages, list of broken URL's and XML file contents. Download the generated sitemap and upload it to the 'public_html' folder on your site. Finally login to google webmasters account and add the sitemap URL.