I've read somewhere that two quantum-entangled particles can be used to communicate over large distances. I wonder if the distance were interstellar, would the photons that travel between them automatically find the target, without any need for a targeting mirror, as in a laser transmitter ?

The key problem then would not be transmission, but delivering a tiny storage device to an interstellar destination, carrying one quantum particle entangled with another back on Earth. I've previously proposed the Relativistic Interstellar Torpedo (RIT) to accomplish this task:

The RIT is a thin needle-shaped torpedo with a mass of a few grams or less. It is a marvel of nanotechnology. It is launched at 99.999 percent lightspeed toward a destination star system. Due to time dilation it arrives there in just 7 days, and carries an onboard antimatter power supply for that short duration. The antimatter powers a transmutation shield at the forward tip of the RIT, which uses inelastic collisions with antiprotons to convert incoming matter & energy (debris) into neutinos, which, lacking substance, then pass harmlessly through and aft of the Torpedo. Upon arrival at the destination the RIT fires it's nanogram quantum entangled payload aft at exactly the same speed it is travelling forwards. The quantum entangled particle communicator is thereby placed in orbit around the alien star system. Having exhausted it's power supply the Torpedo's shield finally fails, and it is destroyed by the first piece of space dust it collides with. But now we have a device that can collect information and transmit a signal back to Earth, without need for a huge targeting mirror, or a high powered laser.

Opinions?