i agree with sewmuch, i have heard it said on some of the quilt shows that putting a quilt on a bed, or even several on one bed is a good way to store.
if you want to store it away you can get acid free tissue to line the quilt before folding. and refold periodically. they tend to wear along fold lines.
i have seen on a show about storing old quilts that some actually roll the quilt around a core of wadded acid free tissue. just be sure that the acid free tissue is archival quality. this just means that the tissue contains a buffer against future acidity.
also, don't store your quilt in a cedar chest. the acid in unfinished wood will speed the aging process.