The behavior of molecular and polymeric fluids adsorbed within microporous solids plays an important role in many technologies. We apply a recently proposed statistical mechanical model which combines ideas found in two different formalisms: The polymer RISM theory of Curro and Schweizer, and the integral equations of Madden and Glandt for a simple fluid adsorbed within a random porous solid. These approaches yield a detailed systematic microscopic model for the structure of flexible polymers in microporous materials. We have obtained numerical results for the structural properties of ideal polymer melts confined within a matrix of hard-sphere obstacles.