  We study the d-dimensional random Ising model using a Bethe-Peierls
approximation in the framework of the replica method. We take into account the
correct interaction only inside replicated clusters of spins. Our ansatz is
that the interaction of the borders of the clusters with the external world can
be described via an effective interaction among replicas. The Bethe-Peierls
model is mapped into a single Ising model with a random gaussian field, whose
strength (related to the effective coupling between two replicas) is determined
via a self-consistency equation. This allows us to obtain analytic estimates of
the internal energy and of the critical temperature in d dimensions.
