All I can say is post it on Craigslist or Angie's Marketplace and on bulletin board at local farm supply and feed stores and someone may take you up on it. A bit risky, though - if someone gets hurt on your property taking it down, you could have quite a liability.
Personally, since corn crib lumber is not in very good condition as a rule, and very little of it is sizeable timber so its value as lumber is limited to shed or barn use, I would just burn it in place if at safe distance from fuel tanks and other buildings and trees and if allowed in your area, or have a trash hauler come in and tear it down and eiher move it to safe place to burn or haul it away.
Another possibility, if at safe distance from houses and such, is ask your fire department if they want to burn it down as a fire training exercise.
One other possibility, though still liability issue unless you have it torn down and stacked, with nails all removed, first - is call local high school football coach and see if they want the wood for a homecoming bonfire or such, or maybe local scouting council or similar group to see if they want it for campground bonfires. Of course, once torn down and nails pulled and stacked, you should be able to give it away as firewood pretty easy on Craigslist or with a sign out front.
