Just a quick link to a neat tool I found through Page Traffic yesterday. Check out GetListed.org. When you are first adding links to your website, the best place to start is on local business pages. GetListed can show you, in a matter of seconds, if your business shows up on the most common of these pages: Google, Yahoo, WindowsLive, and Best of the Web.
Even if you have optimized your site, take a moment to make sure your listings are current!