To appear in the Search Engine Results Pages for multiple physical locations, optimize a separate page for each of your addresses.

 Here are some tips for optimizing those individual location pages:

• Put the location in the page title. An example: Littleton CO- Dell Authorized Computer Repair and Aurora CO-Dell Authorized Computer Repair.
• Mention the location again in your meta description. Example: Certified Dell PC technicians in Littleton Colorado. Call today for fast service. (303) 555- 1111
• Use that location again in a bolded h1 tag near the top of the page.
• Make certain the shop’s physical address appears on the page, including the zipcode.
• Use terms that identify the page as associated with the location. For example, if you are in a particular neighborhood (northwest Aurora), near a local landmark (Denver Tech Center) or close to an important intersection (Exit 115 of I-25), use those terms in the text on your page.
• Point to your location pages from other pages within your site, using good anchor text links that include the location. 
• Use unique text on every location page. Do not simple change the addresses.
• And while it may or may not help with the Search Engines, it’s always nice to show a map for your human visitors.

It’s also important to put information about all of your locations into your local business listings in Google Maps, Yahoo Local and Windows Live Local.