I have a pocket PC with windows mobile 5 and I have put the so called iphone skins on my pocket PC. You need two programs called WisBar Advance Desktop and WisBar Advance before you put the skin which can be found here.
Here is why apple is sending take down notices, because this is not just skin. All the things you see in the skin work like iphone. For example the time is actual clock not just a photo. You see the slide to unlock even that works. Rather than sliding you just tap on that area to allow a pop up bar to come in its place with icons.
You see the small round circles at the edge of the icons and Steve bragged how they would be able to show you the missed call or new messages. They too work like an iphone those numbers change as you get calls and messages.
Even the ipod icon works and opens windows media player.
This skin can be modified as you want which I think apple iphone cannot be done. You can change any icon and assign it to any app.
This skin does something's even better, When you click on the phone app its pops up a small bar on top that you can put photos on and provide phone numbers. From now on just hit the photos with your hand or stylus to call that particular person.
Once you install it and see how better than iphone the UI looks you will know why apple sent take down notices. When you can do what an iphone can do for just half the price of an iphone, they have to be scared.