The image above was shot by Jason Mullins with his iPhone 4 on a flight from London to Guernsey. The weird black lines you can see are actually distorted, disconnected copies of the propeller blades, but this isn’t a Photoshop trick; this was how the image came out of the phone. This is called rolling shutter capture, or Stroboscopic effect. You can see more like this in the rolling shutter Flickr group.
Here is another example of the Stroboscopic effect