Before you register, read Obtaining a Maps API Key to understand how your Maps API Key is used in your Android application, why it's needed, and how to generate an MD5 fingerprint based on your developer certificate.
Use the form on this page to register with the Google Maps service and obtain a Maps API Key. Registration is free.
If you are developing an Android application that will display Google Maps data using the API provided in the Maps external library, you must register with the service and get an API Key.
A single Maps API key is valid for all applications signed by the corresponding developer certificate. For more information about signing, see Signing Your Applications on the Android Developers site.
To register for a Key, you also need a Google Account. Once you register, your Key will be associated with your Google Account.