We were just at a craft fair where a person was selling wine bottles with lights in them. The bottles has the labels available from Dollar Tree, and had a rust-looking spray on them. My wife sez that the spray is available at craft stores - it has a rough, rust-like texture and color. It was very effective.
Edit: I just searched the Michaels website and found something caled "Sophisticated Finishes". It is a 2 part spray, one is a metallic, the second creates a patina. It looks like that is what was used.