Okay, I know the anti-stat bags are recommended, but I have stored 100's of of circuit board for many years with absolutely no problems by just placing them vertically in a box (like record albums) even touching each other.
Boards are not really fragile and the danger of static discharge is not great unless you handle them poorly. As a matter of fact, the real static danger is to components that are unmounted like CMOS chips. These should be placed in conductive (usually black) foam. The idea is not as much to protect from static but to keep all of the pins at the same potential.
The greatest danger of long-term storage is from oxidation or leaking memory batteries. Remove any batteries present and keep your boards in a cool, dry place. As in a previous post, avoid using cling-wrap! It is non-conductive.
If you are afraid of static, place a layer of foil on the bottom of the box to make you feel better. That should keep everyone happy.