  A general method for calculating \NLO cross sections in perturbative QCD is
presented. The algorithm is worked out for calculating $N$-jet cross sections
in hadron-hadron collisions. The generalization of the scheme to performing
caclulations for other QCD process, such as electron-positron annihilation or
in deep inelastic scattering is also straightforward. As an illustration
several three-jet cross section distributions in electron-positron
annihilation, calculated using the algorithm, are presented.
