"Slim is an old friend, and has been involved in this from the beginning," Negroponte said.
The XO laptops went into mass production last month amid fears that orders would be slow as the price per unit had nearly doubled from the projected US$100 to US$188.
Despite early enthusiasm the Nigerian government recently decided to go with Intel's Classmate PC instead.
Negroponte had accused Intel of trying to sabotage the OPLC project, although the chip giant has now joined the board of the not-for-profit foundation.
A recent two-for-one deal, in which Western consumers could buy one XO laptop for US$399 and send one to the developing world, is also proving very successful.
The deal is taking in $2m worth of orders a day, according to Robert Fadel, the Foundation's director of finance and operations.
Fadel added that many buyers are asking for both laptops to be sent straight to poorer users, and that the 'Give Only' project had generated thousands of sales.
Negroponte was dismissive of the pending