One of the main obstacles in AOSP devices is the lack of Google Play Services, also sometimes referred to as Google Mobile Services, or GMS. Included in GMS is the ability to install and use applications that were written to use the Google Maps API. This limitation can be overcome by installing GMS on your AOSP device. We previously wrote about installing the Maps API 1.0 files on Android AOSP devices. For Maps API 2.0, you can install a compatible version of GoogleServicesFramework.apk and Vending.apk (for Google Play) and related files. (As of February 28, 2013, the latest Play Services is version 3.0.) You can often find these files for devices that are supported with CyanogenMod or other custom ROMs.
One option for the lack of Google Maps API is to use an alternate mapping service. The rest of this article provides information to those wanting to integrate maps into an application on an AOSP device that does not have the required Google Maps services installed. It also provides options for maps that may have more flexible licensing.
One of the best options for replacing the Google Maps API is OpenStreetMap (www.openstreetmap.org). OpenStreetMap (OSM) has a lot of Android applications using their programming interface and mapping data. The street map data for OSM is quite good and has flexible licensing (attribution-based licensing, no fee). Users can contribute edits to the data in a wiki-like manner. Some companies use OSM as an alternative to maps built by commercial vendors like Navteq.
ESRI is the 900-lb. gorilla of the the GIS world. ESRI provides ArcGIS online map services at no cost. However, deploying such applications requires an ArcGIS Online account, which is a fee-based service. (I.e. the developer kit and access to your account is free.) Developers can access the maps using web mapping APIs. ESRI also supports an ArcGIS runtime SDK for Android. ESRI is a good option for those already deploying other ESRI-based applications and services.
A couple of additional sites to visit are MapMart and MapServer. MapMart (www.mapmart.com) is a company that provides a wide variety of Internet-based maps. Launched in 1997, they have collect a huge amount of geospatial data. MapServer (mapserver.org) is an open source map server. It allows you to import and provide access to customer-owned map data. The server provides an OpenGIS Web Map Server (WMS) programming interface.
Google Maps has a lot of advantages, including the army of Google engineers working on it. However, it does not need to be the end of the search for good mapping tools. OSM and other mapping options are available to meet your technical and business needs.
Update 28-Mar-2013: OSM also includes a programming interface, 'osmdroid' that is mostly compatible with Google's MapView class for Android.
Google Maps 1.0 API is now deprecated and they are no longer providing keys to use the interface. Programmers must use Maps 2.0 or higher API now, which requires OpenGL and Google Play Services.