  In order to calculate cross sections with a large number of particles/jets in
the final state at next-to-leading order, one has to reduce the occurring
scalar and tensor one-loop integrals to a small set of known integrals. In
massless theories, this reduction procedure is complicated by the presence of
infrared divergences. Working in n=4-2*epsilon dimensions, it will be outlined
how to achieve such a reduction for diagrams with an arbitrary number of
external legs. As a result, any integral with more than four propagators and
generic 4-dimensional external momenta can be reduced to box integrals.
