Ultranium 4 (iPhone iPod)
CheatingDome.com
Accelerometer
Do not forget you can also use the accelerometer to control the ship, which can be useful when your finger gets in the way.
Collectible
Keep an eye out for a collectible called Exit. It skips to the next level and can be a real gift.
Firing
Activating the ship's guns can be very irksome, so once they are firing do not let go.