  We consider phase transitions in 2d XY-like systems with long range
dipole-dipole interactions and demonstrate that BKT-type phase transition
always occurs separating the ordered (ferroelectric) and the disordered
(paraelectric) phases. The low-temperature phase corresponds to a thermal state
with bound vortex-antivortex pairs characterized by linear attraction at large
distances. We show that bound vortex pairs polarize and screen the
vortex-antivortex interaction leaving only the logarithmic attraction at
sufficiently large separations between the vortices. At higher temperatures the
pairs dissociate and the phase transition similar to BKT occurs, though at a
larger temperature than in a system without the dipole-dipole interaction.
