I have seen a lot of technology for the blind, and I can safely say that the iPhone represents the most revolutionary thing to happen to the blind for at least the last ten years.

Amazing article about how the iPhone changes a blind man's life. Make sure to read it till the end, it's worth it.

As a side note, I used to ask interview candidates to design a cellphone for blind people – never did a candidate suggest an almost buttonless slab of touch screen.