Google recently created the Google Webmaster Tools Quick Start Guide which covers the main features of Google Webmaster Tools and will help you to get started right away. If you are new or unfamiliar with Google Webmaster Tools this is a great resource. Each of the main areas of Google Webmaster Tools is outlined with information on key functionalities. Google Webmaster Tools is a great resource for viewing which of your pages are included in Google's index, see any errors encountered while crawling your site, find search queries that list your site as a result, find out which sites link to yours and more. As an e-commerce site we consistently use Google Webmaster Tools to make sure that our sitemaps are working correctly, Google is indexing our site effectively, we are up to date on terms that we are ranking for, and so forth. For those that want to collect this information the quick start guide is a good place to get started.