Forum Nokia just released and useful AIR tool for mobile prototyping: Flowella.
Flowella is an easy to use tool that enables designers and developers to create design prototypes — without writing a line of code. Prototypes are built using images of screen mock-ups and defining links between the screens. This information is then used to create an Adobe Flash Lite 3.0 application or Web Runtime (WRT) widget. These applications can then be run on one of over seventy Nokia devices or in a simulator supplied with Flowella, enabling the application interaction to be assessed.