In nature, ferromagnetism and superconductivity usually avoid each other --- they rarely coexist. Bringing them close to each other in artificial hybrid structures, however, offers unique opportunities to electrically manipulate (e.g. using a bias voltage) the magnetic moments by controlling the spin-polarized current flow. I will give a brief overview of the interfacial scattering processes that determine the spin-dependent transport properties of these systems, including spin filtering, spin mixing, and multiple Andreev reflections. I then explain how spin current flows in Superconductor-Ferromagnet-Superconductor Josephson junctions, and present theoretical results on spin-transfer torque in superconducting magnetic nanopillars.