  We present results of Monte-Carlo simulations for finite 2D single and
bilayer systems. Strong Coulomb correlations lead to arrangement of particles
in configurations resembling a crystal lattice. For binary layers, there exists
a particularly rich variety of lattice symmetries which depend on the
interlayer separation $d$. We demonstrate that in these mesoscopic lattices
there exist two fundamental types of ordering: radial and orientational. The
dependence of the melting temperature on $d$ is analyzed, and a stabilization
of the crystal compared to a single layer is found.
