There are two simple ways of telling Google and the other search engines where your business is located via your website. One is to create a KML file and an attendant geo-sitemap. The other is to provide your full business contact information in rich snippet format on the site. Now there is a way to easily do both with one simple creation tool from Michael Borgelt of 51Blocks.
From a single input of your basic NAP + web information, the tool creates a kml file, a geo-sitemap file pointing Google to the KML file and an HTML code snippet in the new schema.org format for your business contact info.
You then paste the code snippet onto your contact us page or into the footer of your website, place the kml & geo-sitemap files in your public html file of your site and then reference the geo-sitemap file from the Google webmaster tools. The KML file can also be uploaded to Google MyMaps to create an embeddable direction and location map for your website.
I doubt that Google needs both signals to trust your site but by doing both you have future proofed your site for any eventuality.