The PHOBOS multiplicity detector provides measurements of the angular distributions of charged particles over nearly 4-pi at RHIC. In this analysis, we present a systematic study of two-dimensional (eta,phi) two-particle correlations in p+p and d+Au collisions. The data exhibit a near-side and away-side correlation structure in azimuthal angle, which we study as a function of pseudorapidity. Our measurements provide reference information for the study of multiplicity fluctuations and angular correlations (e.g. elliptic flow) in nucleus-nucleus collisions. In addition, comparing the pseudorapidity and centrality dependence of the observed correlations in p+p and d+Au collisions allows us to test nuclear effects, in particular in the unique forward acceptance of PHOBOS.