  The Sherrington-Kirkpatrick spin-glass model is investigated by means of
Monte Carlo simulations employing a combination of the multi-overlap algorithm
with parallel tempering methods. We investigate the finite-size scaling
behaviour of the free-energy barriers which are visible in the probability
density of the Parisi overlap parameter. Assuming that the mean barrier height
diverges with the number of spins N as N^alpha, our data show good agreement
with the theoretical value alpha = 1/3.
