Hey, this is really really an interesting new feature! You can actually control the speed at which Google spiders your website! Amazing, isn't it?
Google Webmaster Tools (previously called Google Sitemaps), provides you with interesting stats about how often the Googlebot (Google's web spider/crawler) is actually visiting and crawling your site. The amazing thing is that you can even control the frequency by which the Google Bot is visiting your site to make it either visit your site more often or less often than it normally does. The stats show on a graph plotted against time the number of pages the spider has crawled in your website per day, the number of kilobytes it has downloaded and the time it spent downloading your web site pages each day.
Kudoz again Google.