The fact that at least three pamphlets dealing with woodpecker damage are available on the Internet attests to the widespread interest in this question. Recommended solutions can be found at: http://www.entm.purdue.edu/Entomology/ext/targets/ADM/ADMPDF/ADM-5.pdf (requires PDF Reader, download free reader), http://edis.ifas.ufl.edu/UW050, and http://migratorybirds.fws.gov/pamphlet/pamplets.html. Although most suggestions on the three sites are in general agreement, the different authors disagree on the role that nearby dead trees and bird feeders may play in woodpecker damage. Hence it is worth reading all three before taking action, especially if eliminating dead trees or bird feeders are on your list of remedial actions. Obviously, although woodpeckers are protected nationwide, the information dealing with permits for lethal control noted on the University of Florida site only applies to Florida residents.

Finally, although one of the authors points out that there is no proof that paints or repellents reduce woodpecker damage, I can relate that extensive woodpecker damage to my own home stopped immediately when I restained my cedar siding with an opaque or "solid" stain in place of the transparent stain that I'd used previously. That was eight years ago, and the critters haven't touched it since, though they are still abundant in the neighborhood. May be mere coincidence, but it might also be worth a try when you next repair or restain your damaged siding.