  We improve the theoretical predictions for the production of extra neutral
gauge bosons at hadron colliders by implementing the Z' bosons in the MC@NLO
generator and by computing their differential and total cross sections in joint
p_T and threshold resummation. The two improved predictions are found to be in
excellent agreement with each other for mass spectra, p_T spectra, and total
cross sections, while the PYTHIA parton and ``power'' shower predictions
usually employed for experimental analyses show significant shortcomings both
in normalization and shape. The theoretical uncertainties from scale and parton
density variations and non-perturbative effects are found to be 9%, 8%, and
less than 5%, respectively, and thus under good control. The implementation of
our improved predictions in terms of the new MC@NLO generator or resummed K
factors in the analysis chains of the Tevatron and LHC experiments should be
straightforward and lead to more precise determinations or limits of the Z'
boson masses and/or couplings.
