Under Clouds makes consistently the best games for the iPhone/iTouch and Penguin Attack is no exception.  This is a great, addictive game that is difficult, slick and definitely not like many others.  Your goal is to slide your penguin(s) across the ice to bump various bad guys off your ice block and into the water.  But watch out because you trade off moves and they're trying to knock you into the water as well.

As the game becomes more difficult new characters will appear.  A screenshot of the help menu is below.