Over at SEORefugee, a couple of threads have been focusing on optimizing for local traffic (i.e. Web Design San Diego). EarlPearl is definitely a local SEO guru, and I suggest everyone pay attention when he discusses the matter. I mentioned some tips that EarlPearl has since taken to calling the DD Method, so as a joke, I am officially claiming it as mine right here. *grin*
Basically, in this thread, rmccarley wanted help getting his client ranked for various towns in certain counties. As it turns out, the client's niche is a photography studio. The DD Method, then, was to use a portfolio and testimonials that referenced the towns for each. So, if the studio had taken a picture of a high school graduate standing under a tree in some park in some town, the photo caption could be something like "Joe Graduate from SomeTown, CA". The same method could be applied to testimonials from "John Doe, AnotherTown, CA". By sprinkling the names of the towns (in a legitimate context) throughout the site, the search engines can get a focus of what locales are relevant for that site.
To get the full use of EarlPearl's knowledge of the subject, check out the thread mentioned above as well as the one titled Observations on the Google Patent for Local Search. You'll get far better, in-depth knowledge of some of EarlPearl's wisdom, than by merely following the simple DD Method.