If you've tried any of the bigger, beefier Android games, chances are good you likely have come across an initial asset preload method which goes something like this: The application APK downloads and installs from the market, then on first launch, the app reaches out over HTTP and downloads assets over the web which it locates in /sdcard. A good example of this behavior is GTA III which does exactly the above.

Back at Google I/O 2011, Google announced that it would eventually allow developers to host up to 4GB of assets on the market. Today, the Android Market rules are changing to allow exactly that. Developers can now host assets on the Android Market (as opposed to rolling their own hosting and storage, out of pocket), and Market now provides a streamlined means for these assets to be preloaded. Application APK size remains limited to 50MB, however, developers can now include two 2GB expansion stores in whatever format they choose, which are stored in shared storage on the client device. On newer devices, the expansion files are downloaded automatically after the main APK, and on older devices developers can  use a Google-supplied library to manage the download. 

This brings total application size up to 4GB of assets + 50 MB for the actual APK. Google has more details about the APK expansion files up in their developer's guide as well.

Source: Android Developers Blog