Who is going to monitor this distribution?

According to a statement in its website, OLPC is not at all involved in the actual distribution (in the countries, to children) or the processes governing it—those are national prerogatives of the countries buying the laptops.

This means it limits OLPC's responsibility once the laptops are handed over to the participating governments. The buying governments also have the full rights on the choice of distribution and implementation of the laptops in the countries.