the best and the most effective sitemap generator for joomla 1.5 and joomla 2.5 is Xmap component this component generate sitemap for your joomla site easily, you can include or exude any menu that you dont want to display on you sitemap and you can also restrict bot from accessing different areas of your website. to get the site map visit joomla extension directory and search foe xmap extension download and install it to your joomla site after the installation go to your components menu and select xmap to configure the site map generator, this site map generator will genrate site map for google news, your images and google webmasters tool, this allow google bot to index your images through your site map, after you have install the xmap it will generate a link at the administrator end that you will submit to your google webmaster tools account. this will increase your site ranking and make it easy for google to index your site contents, you can also create a sitemap page by going to any menu and click on add menu in the menu option select xmaps and name the menu SITEMAP so that bots can identify your sitemap while crawling your page. when we are speaking of CMS everybody know that joomla is the perfect solution for all users. am not a joomla official but i just love joomla.
Joomla gives you the tools and power to build standard sites, directories, intranets, social networks, shopping carts, and so much more. For finding Best google sitemap for joomla please visit: extensions.joomla.org/extensions/structure-a-navigation/site-map