A large class of string compactifications are warped products of the compactification manifold and our four-dimensional spacetime, where the spacetime metric depends on the position in the compactification manifold. New, calculable regimes will arise when warp factors are large and when several different regions with interesting physics are spatially separated in the compactification manifold. We discuss a variant of the Randall-Sundrum scenario which, at low energies, captures the essential features of this regime. We discuss the low-energy effective theory of such a scenario, including the important scales and leading irrelevant operators. We comment critically on the conjectured relationship between the Randall-Sundrum proposal and the AdS/CFT correspondence. Finally, we discuss some phenomenological consequences of these models: namely, a new mediation mechanism for supersymmetry breaking, and a dark matter candidate which might explain some puzzles in the structure of galactic dark matter halos.