  The Kondo effect in quantum dots attached to ferromagnetic leads with general
polarization directions is studied combining poor man scaling and Wilson's
numerical renormalization group methods. We show that polarized electrodes will
lead in general to a splitting of the Kondo resonance in the quantum dot
density of states except for a small range of angles close to the antiparallel
case. We also show that an external magnetic field is able to compensate this
splitting and restore the unitary limit. Finally, we study the electronic
transport through the device in various limiting cases.
