Google Webmaster Tools is a simple set of tools for people who own and/or manage their own domain.  It includes services for crawl errors (not found, unreachable, etc.), robots.txt analysis, search query statistics, and sitemap validation.  What's cool about the whole thing is that it's done automatically; the webmaster doesn't need to download any files or include any javascript.  It's simply a set of statistics from the Googlebot, organized in an easy-to-read format.  But to make sure everything runs smoothly, it's helpful if your site has a robots.txt file and a sitemap.  Mine didn't, so I used Wikipedia's guidance and the Google Sitemap Generator WordPress plugin.  One major issue it brought to my attention was that a couple of my posts were "Not found" by the Googlebot but easily found by me.  I figured out that the problem was that the "Post Status" was set to "Private" within WordPress.  I'm not sure how this happened, but I fixed it and now everything works.  Also, one of my recent posts had some dirty links in it, and Google didn't know what they meant.  I added a rel="nofollow" tag to them, which should do the trick.