App 2 SD helps you to move applications to either internal or external storage through the system settings.
The main window contains three pages, On phone, On SD card and Phone Only.
On phone Page
This window lists the applications that are installed on the internal device storage. You can move an application to SD card by tapping the application icon. Long-press the application icon will show you more options. Please note that only movable applications will be listed on this window.
On SD card Page
This window lists applications that are installed on the external storage (SD card). You can move an application to the internal storage by tapping the application icon. Long-press the application icon will show you more options.
Phone Only Page
This window lists applications that are installed on the internal device storage and they do not allow you to move them to the external storage. Tapping the application icon will bring you to the Android Market. Long-press the application icon will show you more options.
Why not all apps can be moved to the external storage?
Beginning with Android 2.2(froyo), developers can allow their applications to be installed on the external storage (for example, the device's SD card). This is an optional feature developers can declare for their applications. If developers do not declare it, their applications will be installed on the internal storage only and it cannot be moved to the external storage. If you find any non-movable apps, please kindly email developers(not us) for details.
Apps that should not install on the external storage
If app uses any of the following features, it cannot be installed on the external storage. It's required by Android system.
App Widgets, Services, Input Method Engines, Live Wallpapers, Live Folders, Alarm Services, Account Managers, Sync Adapters, Device Administrators