Although Google will eventually locate your site and spider it and hopefully start indexing your pages on a site. Using Google web master tools will speed this process up and also provide additional support for your site, telling you if software needs to be upgraded or your site has been compromised and infected with malware.
Using a google approved site map in web master tools speeds up google's ablity to locate pages on your site.
Contact us now if you want your site added to google web master tools.