Read this, it's what I wrote two-years ago regarding riding a bicycle in MPLS winter conditions.
Since then I have acquired a few more wool base-layer items (short- and long-sleeved shirts, all my socks, head beanie, glove liners), which I cannot stress enough for keeping you warm and dry. I also just recently scored a used pair of Lake winter cycling boots; I'll be getting those ready to go in the next few days, but haven't used them yet.
[edit - my friend Rich rides with Mukluks during the winter months and swears by them, as does Andrew in this here comments section. Damn me for not mentioning them and again for not having tried them yet.]