Google Webmaster Tools
Google Webmaster Tools is a set of pages that allow you to perform certain functions and track various statistics about your site. These tools are completely optional. For more information about these tools, including an explanation of files restricted by your robots.txt file, see this Google Webmaster Tools TNT article.
Since you set up an account before submitting your sitemap, you do not need to do anything else with these tools unless you enjoy tracking and studying stats.
How To Track Effectiveness
By monitoring spider-tracking and index-reporting in the SE HQ, it's easy to check for Google visits (especially after you create new pages), AND to personally track the efficiency of the Sitemaps program.
Go to SE HQ and in the Submit-Spider-List Report, take note of the last date a Google spider visited some or all of your URLs. Also check the dates when pages were indexed.
Return in a month and compare. Note the results for any new or modified pages, as well.
Be patient. If the Google spider is coming, and if more and more of your pages are being indexed, all is going accordingly.