If most of your business comes from a particular city or area you should remember to submit your business details to the local section of the search engines. This will help your business float to the top when someone is searching for a business like yours in your city.
In Google you may have seen these searches show up in the Google maps section at the top of the page. Here are some links to the more common local search submittal pages:
Google Local – https://www.google.com/local/add/login?hl=en_US
Yahoo Local – http://listings.local.yahoo.com/
Super Pages – http://www.superpages.com/about/new_chg_listing.html
City Search – https://selfenroll.citysearch.com/
YellowPages.com – http://www.yellowpages.com/sp/contact/update.jsp
Insider Pages – http://www.insiderpages.com/
msn live – https://llc.local.live.com/ListingCenter.aspx
For some of them such as Yahoo, you need a street address for your business as a PO Box will not work. Some of the directories validate your listing by hand so it can take a few days. You may also be asked to answer a phone call with a special code or respond with a code that is sent to you on a postcard. They want to make sure you are who you say you are.
Anyway, it can be a small hassle but will be worth it in higher listings.