Sitemaps Generator traverses the directory structure of your site(s) and creates a sitemap in XML format, zips it up, and submits it to Google for you. Simply install the program, log into the administration area to create your sitemaps and adjust the settings for each one, then set up a cron job to call the program as often as you wish. Each time it is called it can be told to simply rebuild the sitemaps in the system, or to rebuild them and submit them to Google. According to Google's docs you should first submit each one manually first. Then, let our program take over for you, refreshing the sitemaps and sending them in for you!