What's the cheapest way to ship heavy cargo? (Time is not a problem)?

I'm relocating to another states, and that means I'll have to move all of my possession, including my collection of books, which literally counts about 1000. They are heavy, so bringing them on the airplane with me is out of the question. I was wondering how I could ship them with the least amount of fee, while still can be sure that they would arrive. It doesn't have to be fast, I don't mind waiting a couple of months until I receive them. By the way, I'm moving from Southern California to Oregon, if that's helpful.What's the cheapest way to ship heavy cargo? (Time is not a problem)?
Shipping them by truck will be best. There are many different levels of truck shipping. Call FedEx, UPS, your local moving companies ( I don't know who works on the west coast, Mayflower, Allied?), and regular trucking companies. You will find a maze of methods and rates. Pack your books in HEAVY (strong) cardboard boxes, or better yet wooden crates. If the packing is not strong enough to withstand being dropped without bursting you may loose some books.


EDIT Many small packages 30 o 40 pounds are OK, but ONE wooden crate handled by a forklift would be better. If you use a pallet with boxes strapped to it, be sure to label and number (1 of 17, 2 of 17, etc) each box (just in case), cover the entire pallet so that handlers cannot easily see that it can be broken down, and MARK it DO NOT BREAK DOWN