A sitemap is not needed but recommended. A sitemap could be used to improve the search engine coverage of a site. Small sites that are well inter-linked usually do not need a sitemap.
Obviously Sitemap are must nowadays. All search engines first look for sitemap so that they can easily index your website pages. Below is the best google sitemap generator and it pings the search engines google,yahoo,bing,ask automatically. Its good for SEO. http://rapidshare.com/files/39316514...p-generator.7z
I find that manually maintaining one is a pain. So do most people maintain a manual one or use a tool to create one automatically? If using a tool, I think it kinda begs the question, why would google simply not use the same kind of tool?
sitemap is must for used google search engine, if site map submit in put in website then easy to read our website pages by search engine,new pages cached power increased.