I have to admit that I've been too chicken to ride when it gets snowy / icy. Last winter I crashed on an icy patch of a MUP and now whenever I think about riding when the temps are below freezing, I have visions of coming down on the street underneath a truck or something. I need to check out the winter cycling forum for inspiration, tips, and courage, but in the meantime, I'm doing a lot of bus-riding and walking.