Where do you live? I live in Arkansas and acquired some black walnut from a friend. One piece was part of a limb about 14" in dia x 48" long and some odds and ends that could be cut. I found a saw mill close to the house and they cut it into 1" planks for me. I put it under a lean-to with small 1x1 boards between the planks to air dry. It takes approx 3-4 weeks to dry depending on how wet it is.
Also, if you can get any that you can cut in your band saw, square it up and make some boxes out of it. You will be suprised how beautiful the grain looks and how nice the box comes out when the grain matches on all sides.
I would get as much as I could and store covered outside so it can start drying. Look in the yellow pages and see if you can find some kind of saw mill in your area. The place cut mine for $46.00 and I got about 30 board feet from what I had.
Sorry about being long winded. Hope this helps.
Kevin