Google Maps
Likely to be the most important directory of them all. It is unknown how many people use Google Maps since it is blended in with all of Goggle's approximately 1/2 billion visits per month. With Google maps you can add a description, photographs, and a coupon for your business. See Video Below.
Yelp.com offers reviews from users and is important because Google maps and Map quest will draw some of their reviews from Yelp.com. Yelp.com has been growing in popularity over the past several months. 7,719,700 visits per month*. Submission Page
Yellow pages.com is an extension of the ATT phone book. If you purchased a phone book ad from ATT you are listed in Yellowpages.com. Approximately 9,810,200 visits per month* Submission Page