Google Maps is a powerful feature that lets users easily create highly customizable maps to place on their website. With the admin tool, you have many options to choose from and using just one line of code, can show the map anywhere on your website.
The Google Maps plugin is included and installed by default, but if you delete it manually or picked the no-plugin install, then read below:
To install, first download the zip and unpack the folder 'GoogleMaps' into your 'app/Old_Plugins' folder - be sure to chmod this new folder to 755. Then login into your admin panel and click on 'Manage Plugins'. You should see this plugin listed and an option to install on the right side. Simply click that and click continue on the install and everything should be done! You can access the admin area for maps under the plugins sidebar.
Check out the official API Page.