Google released an overhauled version of Webmaster Tools, filled with both major and minor design and functionality changes. The most obvious change is the new dashboard that now links to your site, Top search queries, Sitemaps, and Crawl errors, Sitemap information, Improved menu and navigation — orgainzed into a more logical grouping, making them easier to find and access the information. The new user interface is available at http://www.google.com/webmasters/tools/new. Google says, all sites must be verified before you can access any features in Webmaster Tools, including features such as Sitemaps, Test Robots.txt and Generate Robots.txt.
Full Article: Google WC blog