Free software-only is a given, but the real challenge (acknowledged in the article) is the display--even the cheapest laptop-sized LCDs cost more than $100, so they're looking at funky rear-projection technology. It'll probably be ugly and bulky if they can get it done, but in a developing country that's not a big issue--beats nothing at all.
Considering that there are several palm devices that retail for the $100 range, it seems like something along those lines might be smarter.