Google has launched new thing in XML sitemap which is an important thing in SEO world. XML sitemap will help google spider to know how frequently and when to visit and which pages to crawl on your site. Adding this XML sitemap will help help google spider indirectly it will help your site.
In Matt Cutt’s last interview he told sites PR will affect the number of times google spider will visit your site. Apart from this i will say Google sitemap is also equivalently important because by providing this XML sitemap you are spoon feeding the google bot.
And with this new feature you can add images too. This will help you to optimize your important images of the website. Which might also rank your images in google image search. I would advice everyone to create XML sitemap for your site.