  We study by Monte Carlo simulations the effect of quenched orientational
disorder in systems of interacting classical dipoles on a square lattice. Each
dipole can lie along any of two perpendicular axes that form an angle psi with
the principal axes of the lattice. We choose psi at random and without bias
from the interval [-Delta, Delta] for each site of the lattice. For 0<Delta <~
pi/4 we find a thermally driven second order transition between a paramagnetic
and a dipolar antiferromagnetic order phase and critical exponents that change
continously with Delta. Near the case of maximum disorder Delta ~ \pi/4 we
still find a second order transition at a finite temperature T_c but our
results point to weak instead of {\it strong} long-ranged dipolar order for
temperatures below T_c.
