How to bring your website on top using sitemaps

Google! one of the Internets most powerful (and developer friendly too) search engines has a free service that makes it easier for you to improve your websites coverage within Google's index through its collaborative crawling system. Although, Google does not 'Guarantee' immediate inclusion, But, is still good news for those of you who have just finished building a website and are ready to submit to the top search engines. So, what's this Google's service called?