Google is limited in the fact that it’s spider can only index links that it comes across. If your newly created link(s) isn’t on a page that is being linked to from an already indexed page, then how is Google supposed to know that your link(s) exists?
You can submit your site to google as well as Submit a Sitemap to google 1.) Site submission : http://www.google.com/support/webmasters/bin/answer.py?answer=34397 2.) Once you add your site to Webmaster tools and verify it you can add your sitemap to google using webmaster tool http://www.google.com/support/sites/bin/answer.py?hl=en&answer=100283
I have many sites those are indexed automatically.. I didnt submit anything via sitemap as such. All I did is that as soon as I kept an article, I just submit it to Bookmarking websitses to get indexed quickly. NOTE: if your website consists of some keyword, will have more chances to index quickly (Its just what I've observed)
Sitemaps allow Google to maneuver through your site more easily and index your pages and content. It is essential if you are like me and have a website with thousands of pages. If you have a WordPress site, there are some Youtube videos that can show you how to add a sitemap to your WordPress site. It's fairly easy.