A site map enables search engines to easily find all content on the site by following all the links from the sitemap page(s)
With the implementation of Google sitemaps, discussed in the ‘Google webmaster tools’ section there is no longer a huge need from a Google SEO point of view for a web based sitemap. For other search engines however it would be beneficial to have a few pages on the site that linked to all content currently published. A single page can have overheads on the system for large sites and for the front end user this can be too big to download and view – therefore several pages of links could make up such a sitemap.
The sitemap start page should be linked to front the front homepage as this is the most common page that search engine spiders will access.