  We propose a double-cavity set-up capable of generating a stationary
entangled state of two movable mirrors at cryogenic temperatures. The scheme is
based on the optimal transfer of squeezing of input optical fields to
mechanical vibrational modes of the mirrors, realized by the radiation pressure
of the intracavity light. We show that the presence of macroscopic entanglement
can be demonstrated by an appropriate read out of the output light of the two
cavities.
