Jan Chipchase from Nokia Research Center, Tokyo makes some practical suggestions about modifications to the phone, ecosystem and infrastructure that can be used to improve the mobile experience of non-literate people:
Menus could have additional iconic support and hardware buttons other than soft keys should as much as possible be reserved to one button for one task. A two-way rocker button can confuse and may be perceived as one button. Wherever possible, phone settings should be automated to avoid the need for editing - for example, by default setting the time and date on the phone from the network.
Successful outcomes can be reinforced with audio feedback including for example playing back the number that was dialed prior to calling. Another option is spoken menus, though again this is a non-trivial understaking given the scale of languages and dialects to support. One radical approach could be to replace the digital contact management tool with a physical/digital hybrid that the user could annotate by pen or pencil.
A mobile phone equipped with a sufficiently high quality camera and display would enable the capturing and location shifting of written text, for example taking a photo of a hazardous materials sign at work and showing it to a literate relative at home.
This is on the new info portal for Nokia Research center which also has links to the Nokia opensource site.