Plenty of free and premium themes and plugins can bring Google Maps support to your website. You don’t have to completely change your site to take advantage of this service. Simple Locator for WordPress is a free plugin that lets you add location search to any post type.
You get a shortcode and widget to add location search to your website. Your visitors can simply enter a zipcode and define max distance to find what they are looking for. Of course, you will need to define each location by adding longitude and latitude info. Locations may also be imported as a CSV file.
On the Settings page, you can change measurement unit, map pin, map view, button text, and other features. A bunch of pre-defined map styles are also available.