I just got an email about free bulk shipping from a company that I have used in the past (here in the Mid West), called War Eagle Mill. They have a nice line of organic flours. In addition to traditional bread flours they also have some other products--their blue corn meal is to die for, much better than some other suppliers I have tried. I've actually visited the mill when I was in the area once. It's a nice establishment in a beautiful location.
Just thought I would share the love. You might have to sign up for their newsletter to get the free shipping on 25 pound bags (the current special), but I wouldn't hesitate to do that--they send me emails on a very infrequent basis.