as of today (28 April 2008), freerice claims to have generated 29,600,638,050 grains of rice for the hungry.
according to wikianswers (http://wiki.answers.com/Q/How_many_grains_of_rice_are_in_a_one_kilogram_bag_of_normal_rice), there are 1,829,500 grains of rice in a 50kg (~110lb) bag.
that makes 16180 50kg (110lb) bags of rice. if these figures are true and correct, that sounds like a worthwhile effort to me.