Here's an interesting article: http://www.macworld.co.uk/ipod-itunes/news/index.cfm?newsid=16927
The first line says it all: "The iPhone is running an optimised but full version of OS X" which to me means that VoiceOver is in there. The touch screen is a challenge, but I have been impressed how the other access features do not collide with VoiceOver. OS X has hand writing recognition built in, although I have never tried it. I am confident they could incorporate a method to operate without vision, if they put their minds to it.
