  We extend a perturbative, nonequilibrium renormalization group approach to
multi-orbital systems and apply it for studying transport through two parallel
quantum dots coupled electrostatically. In general, the conductance shows
pronounced Kondoesque peaks at three voltages. One of these peaks disappears
if, as in some experiments, one of the dots is decoupled from one of the two
leads. For an asymmetric coupling to the leads, also negative differential
conductances are possible. This is a genuine nonequilibrium effect,
accompanying the Kondoesque peaks. Moreover, a criterion to distinguish spin
and orbital Kondo effect in such a system is discussed.
