I don't think those work. There is another Youtube video saying so.
http://www.youtube.com/watch?v=nlxhg60KLx0
Apart from that, these passive patches can change the radiation pattern of your antenna, and if you put it on you may see an increase, all else equal, but you will see a decrease in another direction. Overall, there is no net gain. You do not get something for nothing with these. I expect the iPhone antenna is optimized for best overall performance, and would not bother with the i-Tena.