  We introduce a Monte Carlo method, as a modification of existing cluster
algorithms, which allows simulations directly on systems of infinite size, and
for quantum models also at beta=infinity. All two-point functions can be
obtained, including dynamical information. When the number of iterations is
increased, correlation functions at larger distances become available. Limits q
-> 0 and omega -> 0 can be approached directly. As examples we calculate
spectra for the d=2 Ising model and for Heisenberg quantum spin ladders with 2
and 4 legs.
