NOTICE: Not all applications require a registration key.  Only applications that have an "about" screen w/ the option to register online require registration.

To register your application, first open the "about" screen.  In most applications you can find this from the main menu of the application.

Once the about is is visible you *may* have the option to register online using the device's local Internet connection or obtain an application key for manual registration using your desktop computer.  To register using the device's local Internet connection, enter the email address used to purchase the application and press the "Register Online" button (or menu, depending on the application). 

Assuming your device has an Internet connection and the application is properly configured for your carrier's Internet settings, you should get a confirmation dialog indicating whether registration was successful.

If your device does not have a local Internet connection, if you're having trouble registering on the device or if you just like doing things the hard way you can register using the manual, "offline" method.  To register using a desktop computer, first enter the email address used to purchase the application, then select the "Register Offline" menu (or button, depending on the application).  

This should display the application key.  NOTICE: The application key is composed of the numbers 0-9 and the letters A-F.

Visit http://iballreg.appspot.com/ and enter your email address and the application key provided by the application.

Select the "Register" button to have a registration key generated.  Enter this key in the "Registration Code" field on the device and select the "Register" button.  You should see a confirmation dialog if the registration was successful.