I have some mixed feelings about this issue.
Literacy is a serious issue. Most poor people in poor countries are illiterate. But the computers and interent connections that would likely be available for this sort of program are probably not going to handle multimedia well. Without literacy (let's face it, without English), the net is going to have a hard time making an impact.
Plus computers need infrastructure. Electricity. Tech Support. Dry cool places to sit. These don't sound like such a hurdle here, but there, these things are in short supply.
And in the places where these things already exist, there is already internet access. Even in Africa.
Still, I can think of things that would be useful for small rural communities with adequate connections. My dream module would be a server with a few terminals linked to solar generators, a fuel cell, and a bidirectional satellite connection. They would probably have to be environmentally sealed and ready to be maintained remotely.
Voice mail is the most obvious application. Being able to talk to anyone anywhere without paying exorbitant rates would make a difference.
Regional marketplaces. Assuming a Mojo-like e-currency, you could create a system to allow buying and selling of used items, food supplies, art works and other similar things. Traders in the rest of the world could even get involved, trading artworks for equipment and the like. This would help get around one of the key problems in poor countries, which is the lack of a stable currency.
Online Communities? Again, I think voice based is the only reasonable solution to reach a maximum number of people.
What other applications would be realistic and useful for poor illiterate people in rural agricultural economies?