Summing planar diagrams for string and gauge theories

We discuss the problem of summing planar diagrams in both string and field theory using light-cone methods. We advocate the discretization of both x+ and p+ as a useful tool for attacking this problem. We then discuss some technical aspects of this discretization procedure in non-abelian gauge theories. We describe one-loop calculations in this formalism and explain how the Mandelstam-Leibbrandt prescription might be adapted to it