Yeah, people don't usually love the answer that we have for this one at Appiction. It seems like it should be easy since they are so similar, but they are completely different operating systems with different ways of being used. Sometimes a company will be able to cut a deal with you since the art has already be developed and the basic wireframes have been conceived. At Appiction we created a video to answer this exact question for our clients: http://www.youtube.com/watch?v=Y-fdRw1WNYI
