sitemap is a XML version.A site map (or sitemap) is a list of pages of a web site accessible to crawlers or users. It can be either a document in any form used as a planning tool for web design, or a web page that lists the pages on a web site, typically organized in hierarchical fashion. This helps visitors and search engine bots find pages on the site.many online sitemap generating tools are available.sitemap in two classifications.

1.sitemap.html, a webpage with site index.
2.sitemap.xml,a webpage with list of internal pages in your site.

• Why sitemap need:

1.google should index and crawl all index pages in our site.
2.it is used for more search engines
3.seo friendly site need sitemap.xml

• how to create a sitemap:

create a sitemap in not difficult. anyone can write it in XML version. google provide tool for create xml.and also othersite provide this.like http://www.searchenginepromotionhelp.com


to learn more see http://en.wikipedia.org/wiki/Site_map,http://www.xml-sitemaps.com/