  We prove that in closed almost complex manifolds of any dimension, generic
perturbations of the almost complex structure suffice to achieve transversality
for all unbranched multiple covers of simple pseudoholomorphic curves with
deformation index zero. A corollary is that the Gromov-Witten invariants
(without descendants) of symplectic 4-manifolds can always be computed as a
signed and weighted count of honest J-holomorphic curves for generic tame J: in
particular, each such invariant is an integer divided by a weighting factor
that depends only on the divisibility of the corresponding homology class. The
transversality proof is based on an analytic perturbation technique, originally
due to Taubes.
