If you're interested in creating accessories for Android and the Open Accessory Protocol but don't have experience with developing Android apps then Handbag is for you:
If you can write a sketch for your Arduino, you can accessorize your Android with Handbag:
Handbag.addLabel("Hello, World!", 20);
Handbag.addButton("LED on/off", buttonCallback);
Handbag consists of an Arduino library and an app installed on your compatible Android device. (Requires Android 2.3.4 or 3.1 and the USB Host Shield.)
The library comes with a number of examples to help you get started including a "multimeter" demo:
Try it out and let me know what you think!