I found this article, which was dated in February. It's quite interesting that it was dated in february but the wallpaper is that of the ipad 3, which came out about a month later. I know these could easily be fakes but how did they get the wallpaper right? Could there be some credibilty? Maybe. UPDATE The lock screen slider is different to the one on ios 5.1. There is a camera icon right next to the slider, possibly making it fake. Or is it?