We study implicit multifunctions (set-valued mappings) obtained from i
nclusions of the form 0 is an element of M(p, x), where M is a multifu
nction. Our basic implicit multifunction theorem provides an approxima
tion for a generalized derivative of the implicit multifunction in ter
ms of the derivative of the multifunction M. Our primary focus is on t
hree special cases of inclusions 0 is an element of M(p, x) which repr
esent different kinds of generalized variational inequalities, called
''variational conditions''. Appropriate versions of our basic implicit
multifunction theorem yield approximations for generalized derivative
s of the solutions to each kind of variational condition. We character
ize a well-known generalized Lipschitz property in terms of generalize
d derivatives, and use our implicit multifunction theorems to state su
fficient conditions (and necessary in one case) for solutions of varia
tional conditions to possess this Lipschitz property. We apply our res
ults to a general parameterized nonlinear programming problem, and der
ive a new second-order condition which guarantees that the stationary
points associated with the Karush-Kuhn-Tucker conditions exhibit gener
alized Lipschitz continuity with respect to the parameter.