  We derive the anomalous Hall contributions arising from dipolar interactions
to diffusive spin transport in magnetic insulators. Magnons, the carriers of
angular momentum in these systems, are shown to have a non-zero Berry
curvature, resulting in a measurable Hall effect. For yttrium iron garnet (YIG)
thin films we calculate both the anomalous and magnon spin conductivities. We
show that for a magnetic field perpendicular to the film the anomalous Hall
conductivity is finite. This results in a non-zero Hall signal, which can be
measured experimentally using Permalloy strips arranged like a Hall bar on top
of the YIG thin film. We show that electrical detection and injection of spin
is possible, by solving the resulting diffusion-relaxation equation for a Hall
bar. We predict the experimentally measurable Hall coefficient for a range of
temperatures and magnetic field strengths. Most strikingly, we show that there
is a sign change of the Hall coefficient associated with increasing the
thickness of the film.
