It’s a small setting that can help your downloads immensly! There are lots of devices out there with low internal memory like the very popular Samsun Galaxy Y and Duos. These users have SD cards and will only keep your app if it installs to the SD card too.
To enable the feature is a simple one line addition in your manifest file. Go edit your manifest, at the top you need to add the line android:installLocation=”auto” just after the “package=….” entry is a nice place. So your first few lines will look something like this:-
<?xml version=”1.0″ encoding=”utf-8″?>
Compile and install your app. Now if you go your device settings, the application manager, find your app and look at the info you will see the “Move To SD” button is clickable, try it, the button changes to “Move to Device” once complete and you can go try run your app to make sure it still works (it should be fine).
The full Google documentation is here: http://developer.android.com/guide/topics/data/install-location.html