Just noticed that the Google Sitemaps team is busy at work. They have just announced that Google Sitemaps now shows more query stats than they did previously. Before tonight, they only showed the top 5 queries that your site was shown in the SERPs for and the top 5 queries that people clicked on to go to your site. Now you get to see the top 20 for each. Pretty cool. They have also made some slight enhancements for people who could not upload uppercase filenames (not sure what that was all about) and some enhancements for when their servers are busy.
A Google Sitemaps account is free and you don’t actually have to have a sitemap available for Google to see these stats for your site…you simply have to sign up and you will see them right away. It is pretty cool.