Local search is a huge, multibillion dollar market. The yellow pages have dominated local in the past, but search engines are constantly biting off their market share. Chris Smith from Search Engine Land predicts that yellow pages will see a further decline in the next four years due to the aggressive push into local by search engines. That's good news, unless of course you own a yellow pages business.
Local Search Services
Google Maps is the second most popular product from Google after "search." To get listed on Google Maps, submit your business through Google Local. Big G is the most aggressive of all the search engines when it comes to local queries. Their top 10 local results with phone numbers are usually all users need to find the right business, without ever leaving the search results page. It's crucial to be there.
Yahoo Local will let you list your site for free. Once you list the site on Yahoo Local, your data will be syndicated with Yahoo Maps.
Live Maps boasts a Local Listing Center, to which you submit your information if you want to see your business featured on the Live Maps service.
There are many more sites that specialize in local search. Some of them are CitySearch, Local.com, SuperPages and much more.
When it comes to maps, I find Google is the most accurate at pinpointing business locations. I believe it's better than MapQuest in terms of technology. Google is trying to add reviews and a social element to the maps, but CitySearch, SuperPages and other niche local sites are still leaders in this field, so be sure to get local listings there as well.
Search Optimization 
